Had a nice little foundation leak during the last rain storm. Installed a drain line last fall to divert two downspouts and front walkway run off away from the house which helped a lot. Front walkway and a big retaining wall next to it ultimately need to be removed and reinstalled with proper grading and drainage. That's going to be a huge and expensive project so for now I'm just replacing all the worn out concrete sealant and hoping for the best.
Id argue 90% of home ownership boils down to trying to keep outside air and water out of the house. If you can do both of those, you're winning the battle.
A big part is also getting the inside water out.
I must cool the inside air or else I'm still outside.
but you also need to exchange the air inside often, so you need ventilation too.