Biggest advice I have is, NEVER feel bad about cutting exercise short if something feels off or too sore/tight. Not only does it generally help to keep motivation up when a "lazy" day isn't a big negative on the track record, but staying healthy is unironically the best way to keep up an exercise regiment.

Getting laid up for a few weeks or getting hurt will have a WAY bigger impact than even skipping entire exercises on a day. It's also really important not to rush back in to exercising too hard when recovering. Especially when you get older and older.

Also if you ever pause or stop for a while, go really easy when getting back in to it!! I've hurt myself several times, and it's basically always been trying to rush back to where I was. (or simply pushing too hard on things that don't even need a spotter). Let slow aches heal even if it makes a whole lazy week. Some athletes let minor injuries go for months and keep playing until one day the muscle/tendon/bone finally just gives, and now they have a major injury from something minor.

I utterly cooked my forearms and couldn't work out for six months simply because I somehow managed to push them really hard without feeling it in the moment, once, during one day of exercising. Like my pain receptors were just turned off. No noises or creaks or pain or anything. The muscles did it, without slowing down much at all, but it was like those stories of big adrenaline rushes: They do something crazy like lift a car, and are literally disabled for months after. Felt like my elbows were being torn in half with minimal strain after for over six months. (could be some arthritic condition showing up, but interesting that it'd be right after straining the area a ton).

Also stretches! For similar reasons. More than being flexible, it helps prevent injuries.