The A/C system in my 1990 300E stopped working a year ago. After a couple of estimates of $1,000-$2,000 for a "proper" repair, I decided that I would live without it for a while and eventually replace the car.
With nothing to lose, I installed a Walmart "Death Kit". I'm very happy with it and it is still cooling very well after 6 months of daily use.
Experience is something you don't get until just after you need it.