I worry I’ll make things worse or open up a spot that was holding together okay.
I get that feeling, but I’ve actually found a gentle probe with a screwdriver can save money in the long run. Once, I skipped checking a “decent” board and ended up with a soft spot under my new floor. Had to pull it all up again... not fun, and definitely not cheap. Sometimes poking around feels risky, but missing hidden rot cost me way more.
I hear you, but honestly, I’d rather poke a little too much than end up redoing work later. I used to just trust what “looked fine,” but once I pulled up a corner and found a bunch of crumbly wood underneath. That cost me a weekend and a couple hundred bucks I hadn’t planned for. Now I do a quick tap-and-probe on everything before underlayment goes down. If it feels even a little soft, I swap it out. It’s not fun, but it’s way cheaper than tearing up new flooring.