Most people aren't that interested in complete manual control over their Polaroids. Which is totally understandable, instant prints should be taken instantly without hesitation.
The problem with cameras 30yrs old, or more, is that they typically arrive in poor shape. Usually the battery compartment is corroded and dust has found its way into all the tiny places within the camera body. Sometimes, the shutter is broken or not correct. All the glass/plastic lenses are probably dirty as well.
The most frustrating part about pack film bellows cameras of the 60s and 70s, except for a few models, is that they take either 3v or 4.5v batteries. Most likely, you can not find these batteries in your local store, and prices online aren't so cheap. The best way to keep your camera in working condition, is to modify it to take easily obtained batteries.
Because the battery mod involves opening and cleaning part of the camera, it is a great opportunity to clean everything and also check the shutter circuits, among other things.
With the introduction of the 300 series of camera, Polaroid added development timers to a few models. Some were mechanical and needed winding. Others were electronic and started with a small switch tripped as film was pulled through the rollers. Electronic timers require their own battery and all models with one have two 3v batteries.
So while this reconditioning is focusing on the 350, the process should be basically the same for any other model which also takes has an electronic development timer; thus having two 3v batteries.