Originally Posted by SmilingSimon
assuming no oil leaks from shocks, shocks do nothing but make the ride less bouncy, or 'dampen' out the oscillations from a bump and smooth it to make for better ride - so judge for yourself if your ride is smooth.!
Some of that is part of the job of the springs--they absorb the impacts, and the shocks keep the body of the vehicle stable and in control. Without shocks a vehicle would be like a clown car, jumping up and down.
With a car or truck you typically bounce the corners of the vehicle up and down and see how long it takes to stop. I'm not sure that is practical with a MH.
As to how long they typically last, the OEM shocks on my 89 Ranger lasted 28,280 miles. The replacements have lasted an additional 173,000 and are still good. We have an older Rav4 with over 200,000 miles and original shocks. The manufacturing tolerances are a lot better now than in the past, so they do tend to last longer (assuming they don't leak).