A classic brass wind-up alarm clock, your cell phone, your kids jumping on your stomach?
Poll to follow.
…bladder?
I’m old.
I said cellphone, because I set my phone’s alarm for the time I need to get up. 90% of the time, however, I wake up a few minutes before the alarm goes off. However, I sleep better knowing it’s going to get me up and I don’t have to worry about it.
I wake up to an alarm about twice a year, otherwise I’m awake well in advance of any alarm.
Circadian clock.
I tend to wake up before my digital radio alarm clock goes off these days. It is rare I need the clock anymore.
I suppose option #3 covers a digital clock radio, set to my favorite classic rock station’s morning show.
Digital alarm clock. Set to 4:42 AM on workout days, and 5:07 AM on non-workout days. No alarm on weekends (unless some activity requires). I wake up like a machine, instantly ready to go – a habit I learned in the Navy (and one that still amazes my wife).
I am a natural early riser, I have flex-time at work, and I almost always get to work before anyone I normally interact with. So I don’t use an alarm of any sort, wake up naturally, and go to work. On the three mornings per week when I commute, this means I usually wake up at 5:00 AM and arrive at my desk before 6:30 AM. On work at home days, I usually wake up around 6:00 AM and start working.
I have terminal insomnia, so it goes like this:
Wake up at 2:30 a.m. due to the TI.
Go to the bathroom as long as I’m up.
Lie in bed wide-awake until 5 a.m., when it’s time to get up to get ready for work.
I reset my alarm a while back to two hours later because I was pulling an all-nighter at work, but did not notice it until yesterday.
Because a large furry creature with a cold nose and a large pokey paw needs to Go Outside and have his breakfast at 5:58am. I would like very much if I could teach him the concept of “it’s Saturday, dammit” but so far with no success.
Regards,
Shodan
Battery-powered analog clock. (With another one set across the room as a backup.)
I don’t even own an alarm clock nor a cell phone nor any other such device. When I travel, I carry a kitchen timer, and I set it to buzz the requisite number of hours I want to sleep. Small (size of a snuff can), cheap (3 bucks), lightweight, reliable, AA battery, never has to be reset for time zone, magnetic with a spring clip. Everything you could want in a clock except the time of day. I have a $5 watch for that.
At home, I go years at a time without ever needing to be up at a certain time, I’m always awake by 6, get up around 7.
Light sleeper, and wake up frequently during the night. I’ve never needed an alarm clock-- I have this internal clock that works to the point that I can usually guess the time within ~5 minutes when I wake up. Usually. Once in a while I be way off, but that’s unusual.
I use my cell phone, it goes off every M-F but not on Sat and Sun. I generally wake up right before it goes off but still want to use it. I’m always afraid I’ll be sick and/or tired and not wake up at the right time some days.
Oh, you mean, “What wakes me up?”. Nevermind…
Did a career in the Nav. I can parse 1MC announcements and even alarms in my sleep - I know when I’m needed, and when I’m not. I know when I have to be somewhere, and when I don’t.
I usually use my smartphone as my alarm, but if I don’t need to be anywhere, I’ll wake when I feel like it - usually right about the time the dogs decise it’s time for their morning stroll. 
If I have business to attend, I’m awake before the dogs - and usually before the alarm. If the power goes out, I’ll be vertical and alert without knowing how I got there - But I WILL be aware there’s a power outage.
If someone - kid, wife, dog, is getting sick, I wil be awake even faster than that. NOTHING can generate teleportation like the sound of a kid or dog getting sick.
Cosmic truth.
Combination of daylight and needing to pee. We haven’t owned an alarm clock since we retired, but can use the cell phone, if really necessary. I’m usually up between 6:30-7:00 anyway.
One of those old flip-number clock radios flips from 5:59 to 6:00, followed by the closing bars of “I got you, babe” and then some jackass tells me not to forget my booties cuz it’s coooold out there.
Every. Freaking. Morning.
Sometimes I feel like I’m stuck in a loop or something.
Cat and/or bladder.
When I have to go to work, it’s a clock radio. Otherwise, who knows - bladder, dog, disturbing dream, eyes popping open…