The box of filters would have you change them every time you smoke a pipe. I think that's overdoing it. I think three or
four smokes per filter is probably fine. You can get away with a number more, but it won't improve the flavor even if
you stick to the same tobacco. But if you are stuck with a pipe on a trip, and no extra filters, I don't think a dozen or
even twenty smokes would be a problem, and if it gets to funky, just smoke the pipe filterless, and adjust to a more
sipping instead of puffing mode, unless you tend to sip lightly anyway. I think changing filter every smoke would be
a waste of energy and pocket change.