I'm in the change once a year camp and always keep a couple of the old ones on board just in case. Just seems to make sense, and as Maine says they are not all that expensive.
Does anyone have any experience with those quick change Speedseal impellor covers ? I figure their greatest advantage is that they use a much better, as in reusuable, gasket than those damn paper things.
“Give a man a fire and he's warm for a day, but set fire to him and he's warm for the rest of his life.” Terry Pratchett