Making the system last longer is a worthwhile endeavor. After my evaporator sprung a leak in 2011, a mere 12 years after the car was built, I replaced it, vacuumed the system down, and re-filled with R134a and I'm dreading the day I need to do the job again. It's only been 7 years without having to add a drop of refrigerant or touch the system. While you can tout the benefits of a swap to a non-factory refrigerant, the fact is that its benefits of being in an R12 system aren't there in R134a systems. R134a systems are designed with parallel flow condensers, expansion valves (in the case of the 300M) designed for R134a (not R12 or R12a) pressures, and a swash plate compressor built for R134a. When swapping from R134a, for optimal cooling, the expansion valve would need to be replaced, or else the evaporator will freeze (likely the real reason a converted system shuts off more, because the temp sensor in the evaporator says it's a chunk of ice and needs to defrost).