JP,
In most clubs, you are required to do some kind of duty as part of your club membrship. That has to be taken into account if you fly with various clubs.

Also. as Renny mentioned, club members will not be happy with you if you "prang" one of their gliders and take it out of flying status for the season.

Another consideration is that you will never have access to the glider you want to fly on the really good days because other members will be clamoring to fly that particular glider too, especially if it's relatively high performance.

To reiterate what Renny said, you need to be very familiar with a glider if you are going to do any serious XC safely. Switching gliders could get you in serious trouble in high stress situations like landing out. "What side is the gear actuation handle?"

I have never regreted buying my own glider. After 15 years I could sell it for the same amount paid 15 years ago.

Chuck Zabinski
"ZC"