At least for me, it had to do with what the marina allows. They would not allow me to take a 35' and stick out the two extra feet. This was the case in 3 marina's that I checked out, so perhaps a regional (SF Bay Area) way of handling it. With that said, very few boats in my marina stick out beyond the end of the slip and very few have a pulpit hanging over the main dock. One thing to consider is that if your motors are up, they are exposed to other boaters if the marina is tight. I ended up with a 50' slip, so another boat would need to come into my slip about 8-10' to create a collision. At least one shorter slip I looked at would have had me sticking out at an end slip with a tight corner - - no real protection from other boats.