Unmoderated studies should be created with a 10-15 minute time limit in mind.
While there is no 'hard stop' and recording will continue past this point, we have found that it's best to try to keep things within 10-15 minutes.
Test participants tend to be most engaged in that time period. If the test goes longer, you may see that they become disinterested in the tasks or may leave the study altogether before coming to the end.
Our panel of testers expects unmoderated studies to last 10-15 minutes and are paid accordingly ($10) for their time. If the study goes longer, the incentive is not adjusted (the system pays this amount automatically and does not allow for individual adjustments)
If you have a study that seems like it will need additional time, you can consider setting it up as a moderated test instead (times are 30, 60, and 90 minutes), or sending the study to your own list of participants (setting the time and incentive expectations as you would like!)