I'm nearly 49 now. Presbyopia (the loss of ability to close-focus) came on strongly for me at about 46. It was almost like an overnight change. I've also lost significant acuity in low light, but that seemed to come on more slowly. I got my first bifocals last year. I got the "no line" variety and, so far, I hate them. The focal distances I need for reading, viewing my phone, and other close work are at the absolute…
Usually only happens when I'm tired. Bifocals are probably in my future though.
If I want to do circuit repairs, I have to do it in the morning though. Detail work is too hard on my eyes otherwise.