Yeah FDTK, I don't know if its just a Bonanza thing or not. A mate has a Baron and he has only done one cell in 10 years! It has two cells per wing though.
Three of the 4 cells that have failed on me have all done so at pretty much the same spot near the fuel outlet teat, where it joins the steel (aluminium?) fuel line. My Lame seemed to think it could be caused by hornets nests (the mungrel bastards) clogging up the vent and causing the cell to suck together pulling on the fixed point of the fuel line. I check the vents very closely with a bit of wire during the pre-flight though, and often find them there and remove them, so I don't know if that is the cause. If the vent is blocked in flight you often find the fuel gauge won't show lower than about half full (when it actually is) and when refuelling the bottom of the cell will ride up and be very close to the fuel cap hole. Blocked vents can be a big problem in flight. I remember reading a couple of incident reports where a blocked vent caused the cell to suck together as fuel burned off and the fuel drain snagged on the lower wing skin and pulled it out, resulting in the whole tank draining overboard
As Norm Colvin says in his Bonanza Bible, keep the tanks as full as possible while on the ground to prolong fuel cell life