The trainer concensus seems to be that strength declines slowly with age, but recovery capability declines much faster. Dropping back to twice or once a week is normal. Even longer recoveries aren’t unknown; Mark Rippetoe mentioned he only squats once every two weeks now. He’s in his late 60s.A lot of trainers get their freak on about their definitions of the difference between "training" and "exercise", exercise being "a useless waste of time." For a competitive lifter, probably true. But when you’re an ordinary guy past your mid-40s, plain old exercise becomes *much* more valuable for general health than it would be for a younger man.
For my part, I’ve been lifting weights for 30 years and while it’s true about recovery not being the same, I think if you keep in good shape then it won’t change much. But I’ve made some adaptations for sure so while it’s squatting 3x a week, even a hard session like 5x5@85% isn’t quite a true max effort cos it’s based off a non-grindy 1RM.
I personally find that if I focus on pushing as fast as I can with a sub-max weight it has a better effect than going heavier but grinding it out. Both for recovery but also strength.