The older I get, the more I don’t mind the heat as much. A little A/C is necessary in some cases, but in others a fan for me is fine. As much as my brain chemistry hates this weather, my body has been in love with it 
My husband, OTOH, needs A/C. He cranks it no matter what room he’s in and in the car. Otherwise he breaks into babbling brooks of sweat.
Most males I know IRL are the same. I swear there must be physiological reasons for this.
Our home is adequately shaded by trees, such that we only have a few real scorchers where it is uncomfortable over night.
Then, six or so years ago my gf went through menopause and was hot flashing like mad. I bought a bedroom air conditioner as a gift for her and it made a real difference. Her hot flashes are no more, but we use the air conditioner a few nights each summer.
Our ac goes pretty much steady from late April to early October. Winter or summer we like the temp in the house no more than 22c during the day & down to 18c at night.
I’ve lived in Florida for the last 25 years and the vast majority of that time I had no a/c, usually for financial reasons. Luckily I’m pretty heat tolerant to begin with and when you don’t have a choice, I guess you just learn to live with it. To me the worse part was not have a/c meant not having heat either which is a way bigger deal to me. Granted, we only have a couple months of cool weather - most of you wouldn’t even consider it particularly cold(highs in the low 60s, lows in the high 30s) but when you’re used to it being in the 80s every day a temperature drop combined with the dampness is very unpleasant.
People lived without air conditioning for centuries, and I see no reason to change my way of life. It’s cheaper, it’s environmental, most public places (i.e. libraries, stores and work places) have A/C, so it gets me out of the house in summer.
In a really, really hot year, we might need/want AC ~10-15 days a year. That’s an EXTREMELY hot year. Most years, it’s 4-7 days a year. Many years, it’s zero days a year.
We once got a bid to put AC into our house. We don’t have the ductwork for it, so we’d need the type that has big AC units mounted on the wall. They’re ugly as hell. Cost was $13K to put them in the main area of the house (a great room that consists of a living and dining room) and the master bedroom. No thanks.
We also have casement windows. You know, the kind that wind open as opposed to sliding up. That makes it impossible to use the really good, cheap AC units as they don’t fit in these kinds of windows.
We did end up buying two freestanding AC units, to the tune of about $500/each. I have one in my office, the other is in the master bedroom. They sorta kinda work - if it’s 95 out, they’ll bring my office down to maybe high 70s. So it’s OK, but not great.
That said, for the ~4 days a year I need AC, it works fine.
I grew up without it, so I was used to not having it. when I moved into an apartment, the air conditioner was a window unit kludged into the wall with some ducting retrofitted. it was so noisy and ineffective I never bothered using it, and being accustomed to not having A/C made it OK. I was facing the correct direction for the prevailing wind to flow through open windows.
now that I have a condo with central forced air heat/AC, I use the air conditioning.
In my case, I’m renting the house and the property owner has central heat installed, but no AC. 11 months or so out of the year, it never really gets warm enough for it to be an issue where we live. So for the other month, we open all the windows and run a couple of fans.
I’m in the UK, it’s mild enough here that a/c isn’t needed at home. The hottest day we’ve had this year is 86F. Houses aren’t built with duct work so central a/c is out of the question. I just went to the B&Q website (UK version of Home Depot type store) and did a search for “air conditioner”. They offer exactly 1 model, a portable one, not a window model.
It’s currently 82F outside and in my home office. Having the windows open and a fan going, plus being able to work in t-shirt, shorts, and no shoes makes it comfortable.
My parents always had an evaporative cooler or two while I was growing up, I got a window A/C unit for my bedroom once I could swing it. My dad, in his last few years, finally got a couple of window A/C units for his living room, still slept in a corner room with windows open and fan blowing. He had plenty of money to install central air, but he didn’t like the idea even though he installed central heat when I was in grade school.
Me, central air all the way. When I remodeled the house I live in now - it was his parent’s house - I put in central air. He told me “it’ll cost you $100/mo to run it!”, I said I’d pay it. Almost 30 years later and I only go past $100/mo a couple of times a year. I don’t think I did at all last year, we never got over 100° F all summer. But my last bill was a record high I think, $145, it’s been hot this summer.
A heat pump was the first thing we installed when we moved into our present home. We got a tax break on the energy savings that helped defray the cost. Many of the homes we looked at did not have AC, and our realtor (and others) kept telling us “Oh, you don’t need AC in Portland. It only gets hot for a week or two in the summer.” For me, that would be enough to have air conditioning, but since it’s total bullshit, upgrading our system was fait accompli.
We barely had a/c when I was a kid. NY area, some nights it’s difficult to sleep without it, for me. We’d have fans then eventually my parents got a room a/c for their room and we were allowed to sleep there on the floor the few hottest nights.
As adult I was OK with window units for night time until recently, and wouldn’t use them all night because of the noise (bothers me at least), we’d cool down the bedroom then use a ceiling fan. But my wife not so OK with that eventually. And it wasn’t really a matter of the money, but stubbornness (on my part) as other posts have mentioned.
Last year we got a mini-split type system for 3 floors of 4 floor house (external compressor unit, pipes carry cooled refrigerant to interior evaporator units in the various rooms, but more work if there are rooms not adjoining an exterior wall or the basement, that’s why not on top floor, our grown kids’ bedrooms now rarely used). That’s pretty much the only practical way in an old house like ours (115 yr old stone row house) if you’re not gut renovating. ~$20k upfront and $100/mo extra electric bill July and August. Well worth it in hindsight.
I struggle to pay my bills now as it is, and in the summer, I get a break on the gas bill because the heat is off, and that helps. I’ve rarely lived in a home with central air and I’m just used to it being hot in the summer (and cold in the winter).
My house has radiators, so central air is out, but on the hottest nights, I have a box window unit I put in so I can sleep and to give the dogs a bit of a break from the heat.I really don’t like the window a/c - it’s loud and I wake up feeling stuffed up, and when I don’t need it, it blocks the only window in the bedroom. But, given enough plus 30C days followed by a few plus 20C nights, the whole house is so uncomfortably hot, I wrestle the unit into the window, prop it up there and enjoy a cool night. Then when the weather cools off, I drag the unit back into the closet and put a fan in the window.
I should get one of the units on wheels, but I’m waiting for the current one to die. I like to think that I am being environmentally friendly, but mostly, I’m just too cheap to toss something that still works.
This is me. I’ve had AC for 30 years in various apartments and I almost never turned it on - the times I had it on, Chicago news was tracking people dying from the heat. So I don’t have it at the house at all as KY’s temps are more moderate (I don’t have central heat either). I rarely feel uncomfortably hot and when I do, I’d rather down a pint of Haagen Daz, as that’s really the only time I enjoy ice cream.
Not that I’m against it. I’ve visited Florida and know that down there, I’d have AC. Actually, I’d have a walk-in cooler with furniture.
I had a teacher in the sixth grade who claimed that air conditioning was invented in Phoenix, Arizona. Given the name of the place, I didn’t think to question that fact for something like two decades.