Generally speaking, the less you spend on the conversion, the shorter it's life will be. You can get cold air cheaply with R134a, but it won't last as long as if you do the full deal. YMMV.

 

It's been a few months. Everything still blows nice and cold. When I had it charged the shop said vent temps were at 34*. This summer working in LA will give it a test. Might need a new fan clutch (233k miles) but that's the only issue I have because sometimes in traffic it's not quite as cold.

Woops, this was actually supposed to go in a different thread but my phone decided otherwise. Here's the thread it was supposed to go in, with my full r134a conversion a couple months ago.
https://www.ford-trucks.com/forums/1...questions.html