Well, it depends on when you post and the type of activity that is happening. There are some times in the day when no one else is really around. So you could be waiting hours for a response. The worst is when you get that and then there is a rush of other questions posted. If your question gets pushed down too far, you could be waiting a day or few for a response.
The reason is that, most of the time, there are enough replying users that threads are answered or in progress with an experienced user by the time they reach the bottom of the first page. So most replying users just assume there is no need to check the bottom of the page; even more so for anything beyond the first page. That said, there are a few users like myself that do occasionally go back and do a second check every few days. Any missed questions usually get answered then.