For the first 4 years of owning a house 95% of all the projects you work on involve creating storage for all of the crap you own for working on projects.
And the left over project materials you drag from the old place to the new because you might need them.
#127: For the first 3 years your projects are all fixing the crap the DIY-useless previous owner messed up.
For the rest of the time you own the house your projects are about half fixing ordinary wear & tear and half all fixing the crap the DIY-useless *current *owner messed up. 
…and you will practically throw a party for every nut, bolt, or foot of lumber that you use from there instead of going on a trip to Home Depot or Lowes…
Waste not, want not!
Your spouse won’t have a clue how to fix something but she sure as heck will tell you you are doing it wrong.
I’m sorry - are you suggesting that you are able to complete a project without going to the hardware store even once, let alone TWICE?!?
I have, neatly organized, nails, nuts, and bolts from my grandparents. Depression generation, which excuses them. I looked at the collection and took it home. And have actually used some. 
Does “changing the positions of all of Mom’s wall decorations to make room for two new ones” count?
And you’ll refuse to consider that the 79¢ bolt you had to get actually costs three times that much when you factor in the cost of the gasoline to drive there… We live in the boonies, and the closest overpriced hardware store is 7 miles away, with Lowe’s more than twice that far, and Home Depot more than 25 miles, one way.
#214 - You’ll suddenly realize that the brand-new kitchen remodel actually happened 11 years ago when your appliances start dying. (Two down, two on death row…)
#39: If one of the reasons you are looking forward to moving into your new house is having a functioning dishwasher again, the dishwasher will break. Immediately.
I said you’d Use them. I didn’t say you wouldn’t break or strip anything else while trying to complete the project. Sure you’ll go & twice will be a low estimate.
Count yourself lucky if you find parking, don’t “impulse buy” three tools* for future projects, and miss seeing the weekly fight in the parking lot.
*Bonus Points if you impulse buy a tool to replace an older one… and when you get home decide to keep both tools…
**Double Bonus Points if you take apart the old tool and try to re-purpose the parts to make a different tool. “See? I can use this to … move logs in the fire. Yeah. Want me to start a fire so I can show you?”
After 27 years in the same house I can tell you the corollary to rule #165. Your possessions will expand to fill all storage. You’ll add more and fill that too. Soon you’ll forget what’s in those boxes. Then you’ll need storage space for the last project: organizing all that crap to get rid of, the way you’ve always meant too, and there won’t be enough room.
#86
If you tear down hideous wallpaper, there WILL be, beneath it, something else so hideous that only wallpaper could fully conceal the horror! It will always be beneath the very last piece you remove.
#86(b)
When you pull up the broadloom, to check the hardwood beneath, before putting in your offer to buy, when you see it is pristine and lovely, you need to remember they laid that carpet to cover something up. Something bad!
Rule #42 - When you require a particular sized bolt, screw or nail for a project, never buy that small packet of a dozen to complete the project. Instead, you always, always, always, buy the 100-piece or 200-piece box of the item. You will find the next project you work on will always, always, always, require that specific bolt, screw or nail you now have a caselot. Thus proving the universality of Rule #42.
All of the above are TRUE!
dammit :mad:
And the worst words you can hear from a workman or meter reader - “Hey mister - I need to to look at this”.
Don’t forget the six-pack and the colorful vocabulary.
…and an Allen Wrench Set. You can ONLY find the Allen Wrench in your home…
…if you buy a new one…
(Clueless non-home-owner here. Fight my ignorance!)
SO WHAT IS HOME OWNER TRUTH NUMBER ONE ALREADY?