The “You bought this” window has saved me a couple of times. 
1979 Fiat Spider. Slid it in a narrow space in the garage at the house down the road. Kinda forgot all about it with all the shit going on. Went down there a while back, and, “Oh! That thing! I better do something with it!”
I think this has to be the thread winner. “I forgot I bought a car!” 
My son is kinda into the smaller kits right now. He’s a bit too young to do it on his own. I want to encourage him because honestly they look pretty awesome. I love putting together puzzles and it seems like a similar thing. But LEGO is a hobby that gets expensive fast!
Amazon Packages mysteriously arrive. I sometimes forget why I made the purchase. It’s usually some kitchen gadget or pan that looked interesting.
I have tools that I bought for a specific project. They’re used once and end up on a shelf or in a toolbox. It’s frustrating to buy something that I already own.
Most recently - found an LL Bean gift certificate from December 1995
An umbrella!
I do not use umbrellas and haven’t owned one in decades. My car is in our garage and when I reach my destination I park as close as possible and run. Or wait a bit for a lull. Or get wet.
A friend of my gf stopped to drop some stuff off for her. When she left it was raining hard. She asked if she could borrow an umbrella, but I told her I did not have one. My gf kept a small one in her car, but she wasn’t there.
As I walked her through the garage I offered her a newspaper. Then she said,”hey, there’s an umbrella!”
It was a huge golf type umbrella that I’d bought at a yard sale for kayak sailing. With good sustained wind an umbrella can be used as a sail, while you rudder with your paddle. It was a one time lark that I never repeated. I gave her the umbrella.
Indeed: the sets I’ve purchased this year have totaled $445. The least expensive was $13 (a joke gift for a friend), and the most expensive was $170. They will all be eclipsed by the $230 jazz club, though…which is why it’s taken so long for me to get it. Oh, and there’s an additional $670 of sets still on my wish list (including a $400 grand piano that I will almost definitely never actually get).
If you don’t mind my asking, how long does it normally take to put one together? Weeks? Months?
So, with the house came some very old tools, including a small, all metal hammer with a prying wedge end. Very handy. During the 22 yrs we’ve lived here I have often scrounged to find the thing, whenever it would, in fact, be THE perfect tool.
I’ve been doing a giant sort, of the house and, low and behold, there are two such hammers, in this house!
Mind blown!
I do also, but Lego sets have the disadvantage of clear instructions on how to assemble them. Even better are Puzz-3Ds, which don’t come with step by step instructions. I’m not sure how much of these are made anymore, I had a lot of them.
Buy the buildings as opposed to the spacecraft, since not having flat bottoms can be an issue. My wife did some PR for the guy who founded Wrebbit, the Canadian company that invented them, and the Star Destroyed puzzle was tough even for the designers.
In all seriousness, there’s no “normally.” It varies based on how many pieces there are, how complex the build is (sometimes those two are related but not always), and — mainly — how much free time I have*. Bigger sets have taken a few weeks because I’ve only spent 1-2 hours on them at a time, 1-2 times a week.
That said, I’ve put a few smaller sets together without stopping: 400-500 pieces took a little less than 90 minutes, while 700+ pieces took a little over 2 hours. Other people could build sets of similar size either faster or slower, though, depending on their dexterity and ability to spot needed pieces, etc. Every now and then I’ll find myself looking through the pieces in front of me for a long time, unable to find one I need, almost ready to believe it got left out of the box…and then I finally see it.
*And how many mistakes I make. 
I was cleaning out the garage and got brave and decided to start clearing out junk from the rafters. There was mostly old construction stuff like 2x4s, moulding, plywood, etc.
Way in the darkest corner I saw a box. I went over there and retrieved it, only to find that it was a mailed package, unwrapped, and addressed to me. I had NO idea what it was.
So I opened it, of course. It turned out to be a childhood favorite game of my spouse’s from the 1960s. I apparently once heard her talking about how much she used to love that game and then bought an original on ebay, then stashed it away in the garage until Christmas.
And then forgot all about it.
I bet it had been up there for 10 years. I have no recollection of ordering, receiving, or stashing the package.
mmm
Lego makes advent calendars. I get my DIL either the Star Wars themed one or the Harry Potter one every year. The items in the calendar only have a few pieces and they’re small.
They sell out fast.
And then what? Don’t leave us hanging, man!
And then I gave it to her, explained that I must have ordered it several years ago, and she said, “oh, cool” or something to that effect.
Now it’s in our “garage sale” pile of stuff to sell.
mmm
Oh well. As long as you got the brownie points.
I found a high school yearbook for my mom on Ebay. It was two years after she graduated. She looked at it once or twice. She remembered some of the people.
It’s on the shelf now. Most likely will go back on Ebay for $5 in case someone else needs it.
It’s was worth buying. My mom hadn’t seen many of the people since school.
Life is all about brownie points. My favorite situation is when I offer to do something for someone, and then the need for my help vanishes. I did nothing, but still accumulate the points for having been willing to do something.
There should be a specific term for that.
My stepson was a master at offering help with a job when it was just about finished.