| Fuzzy-Wuzzy |
Correct.
Try Again: Varies. You can retry checks made to disable traps if you miss the check by 4 or less. You can retry checks made to open locks.
No downside. If you're just going to sit there until you succeed, you could just Take 20 and avoid the rolling, that's what it's for....
| Pizza Lord |
Fuzzy Wuzzy has the right of it. If there's no reason they can't keep trying they should Take 20 (taking 20 times as long, typically 2 minutes) to get it right. Take 10 would also work if they're trying to be faster and don't want to risk a low roll but since most locks will be DC 20 to 25 at worst, you'd need to have significant skill to go that route.
Most players in my experience will make one roll to make a go of it then Take 20. Without time or danger being a factor, the most common thing to consider is a creature on the other side hearing you fiddling with the lock and having two minutes to prepare.