What if you're replying only to continue the line of questioning rather than post a near-identical thread that would basically be a waste of space?
It seems to me (but I don't know this for sure) that posting something as the start of a new thread would use up the same amount of board space (or a very similar amount of space) as adding the post to an existing thread, since you would be putting that frame somewhere either way?
"... it is much more gratifying to change your own world than the whole world." ~Magistra Ygraine
"Life is the great indulgence-death the great abstinence. Therefore, make the most of life-here and now!" ~Anton Szandor LaVey
"The true test of anyone's worth as a living creature is how much he can utilize what he has." ~Anton Szandor LaVey
"Twenty percent of your priorities will give you 80 percent of your production, IF you spend your time, energy, money, and personnel on the top 20 percent of your priorities." ~The Pareto Principle, as stated by John C. Maxwell