Is it a must for freelancers to do free tasks to gain more clients?

[Btaliat]

There are some freelancers that always do this. What they do is that they select a particular time or even days that they want to do that. They inform their clients about this ahead. The aim of this is to gain more clients for themselves. However, some expert freelancers have agreed that it is not really a must for freelancers to do that. In fact, they even conclude that new freelancers should not be doing such.