In the last year, I bought a Leica M4-2 and M6 and both were given CLA. There was other small work I had done (window upgrades) and these now operate like new IMHO. Wasn't necessary per se, but it gave me more confidence that at least I was starting with a solid piece of equipment. WIth the Rollei 6008 I bought recently, I'm taking a wait and see. Some of the things I've noticed might need looking at... but could also be products of my initial unfamiliarity with the camera. Haven't determined whether there's a systematic issue or not, but tending to think not. I rebuilt the batteries myself with inspiration off this list. But for the most part, I'm thinking if I do anything it might be early winter next year... the so-called "off season".
So I'm in both the wait-and-see and fix-it-up camps. CLA doesn't have to cost a fortune, and if you have more than one camera lying around... and most of us do, it doesn't mean you lose any time shooting. I will say this, when I'm done with a camera, I make sure it's in pretty decent shape for my use and has all the bells and whistles needed or that I "thought" I needed. And it's trying not to repeat this too often that seems to have moved me from one camp to the next... and why I'm in both at the moment. No sense in fixing up a camera and gathering all the goodies if it doesn't suit you, and you're just gonna sell it to someone who finds it more suitable. Fix up and gear up only the keepers! And this is a problem because? Well, because if you're buying film cameras, you're buying goods not inventoried in any store or available for rent so far as I'm aware.