If you notice a change in behaviour, that's a sign of stress. In which case they've had enough

When I think of over-handling, I think of someone who constantly disrupts and moves hides to take out their snake several times a day, for long periods at a time. I don't know anyone who does this, but I bet there are those out there who do.

But again as mentioned, every snake is different! Some may be comfortable coming out a couple times a day or every day, while others may only tolerate it once a week or less.

Personally I take my corn out during the day because she is sleeping, and when I get her she's nice and calm and it takes her a minute to wake up. That way she's not spooked by me at night when she's out roaming, and trying to slither away. I usually wait until dusk for my ball python because he's already at the front of the vive trying to get out!