In my experience it seems that most people will tell you that it is unwise to force a garbage collection but in some cases where you are working with large objects that don\
However, if you can reliably test your code to confirm that calling Collect() won't have a negative impact then go ahead...
IMHO, this is similar to saying "If you can prove that your program will never have any bugs in the future, then go ahead..."
In all seriousness, forcing the GC is useful for debugging/testing purposes. If you feel like you need to do it at any other times, then either you are mistaken, or your program has been built wrong. Either way, the solution is not forcing the GC...