I buy the 10 day non expiration with plusses once and then every other trip buy the 10 day non expiration without. A 10 day pass lasts us about 1 1/2 trips as we go to the parks 6 or 7 days and then use the 3 or 4 days the next trip with 6 or 7 days of a new pass.
It's inevitable Disney will always raise ticket prices so as long as I don't have to charge them I buy as many as I can in advance.
We very rarely go to water parks (maybe once every trip), or Disney Quest (maybe once every other trip), or golfing (not that my bf doesn't try every trip

) so those 10 plusses last us a LONG time. I would buy the plusses more often, as eventually we would use them (as long as we were still loving Disney or still alive

), but, honestly, I can barely keep up with how many plusses we have on one pass. I couldn't imagine having 2 or 3 passes with days used up and plusses on them trying to keep them straight (this, of course, would be a whole lot easier if there was a way to go online and check the passes). Some people don't find it a big deal but I can never keep it straight how many plusses I have left. I've tried keeping them in an envelope and writing the date I used what but it never fails I forget to write one down. I in fact did run out of plusses on a pass I thought had one left (didn't check at the resort or ticket counter

) and went to get into TL only to not have any left! (I did have some Disney magic that day as the CM let me in anyways as it was only open a couple more hours and my bf did have one left on his).