I was curious about this via the other thread about the homemade air filter. i know cannisters are better but dont know how much in terms of engine life so here is my deal...................... we have cannisters on all of our ztrs wether it be the kubota diesels or the 25 kaw on our warriors. all the other 17 hp kaw on our standers etc have the regular paper covered with foam stock filters. my experience so far is we dont seem to get that great of hours on those engines b4 starting to have issues especially with oil leaks and rings/valves. 800 hrs seems to be the pont at which most start at least to have symptoms but none have ever gone over 1100 hrs for us. we change oil at 50 hrs, air filters are cleaned as needed or twice a week or so depending on conditions. So, my end question is for any of your with walkbehinds or stand on mowers that have cannisters on the 17 or 19hp kaw engines get less trouble and much more life out of your engines with them for the added cost.??? thanks for sharing your expereinces.