Every few days I get a newsletter from 'The Family Handyman' that is full of lists of 'what to do now'
It was a magazine we used to read years (and years) ago that we still get something out of the newsletters (free)
https://www.familyhandyman.com/My dad was farmer stock, and could do almost anything, as is TheHusbandHalf. Dad built the house I grew up in and I now live in a 1915 house that we've done almost everything to. I don't know where we'd be if we didn't have the upbringing we did, so I feel for you.
TheHusbandHalf looks at a lot of You Tube videos if he doesn't know how to do something. The most recent - he rebuilt the motor for our central vac. It's 35 years old, and now it's like new, all from a You Tube video.
Our refrigerator was leaking, and again, you tube to the rescue. Saved us a repair call, it was actually something simple, but not mentioned in the manual.
I agree with keeping water out. Do you have a basement? Keep an eye on that for water coming in. Keep an eye on water outside - does it flow away from the house? Make sure the lawn slopes away from the house.
Again, use the internet, you tube? to learn how a roof is supposed to look and how it will look when it's wearing out.
Whatever kind of siding your house has, look it over to see if any place looks 'off.'
Are there any places around the windows that could possibly be water damage?
Do your exterior doors seal well? You tube might help there (it's just one of those things we've been doing so long, no you tube needed.
That's all I can think of at this late hour