Depending on mentor, the average response time is between 1 and 5 working days. How fast a mentor responds usually can be seen on their profile.
In some cases – roughly 5-10% of the cases, mentorship requests can go unanswered. This happens more often with free mentors. After 10 days we usually assume that a mentor is too busy, and will send you a reminder with a few suggestions and alternatives to look at.