Consideration To Others

Not sure if this is in the correct forum and
please move to the appropriate one if it is not.

I have noticed some members lately who promise
to buy something from you then never go through
with the deal and or do not even reply to ones
emails pertaining to the deal. Every ones time is valuable.
Some consideration would be appreciated. If you change your mind which often happens, at least please let the seller know.
in a timely manner. Not pointing any fingers but it seems to be newer members that do this more often than not.
Thank you.