How long will they last?...
There's way too many variables, on how they're used, to give ya a good answer. Sorta like "how much gas would your jeep burn in 2 weeks"? You would have to take into account the type of road (flat, smooth, up hill or dn, etc.), the quality of the gas, tire pressure, etc. Do ya see what I mean?
To get an somewhat accurate idea of how long, and short, ur shocks need to be, you should REALLY Flex (compress) the corners until you hit the bump stops or ur tires are hitting something (which means ur bump stops are too short), example right front and left rear, (without shocks or at least not attached @ the bottom) to able to measure the distance between shock mount bolt holes on ur up-travel. As extreme flex as you can get, which might require you going to a shop (or to do this @ home you can remove the springs from the ends you're going to compress). Now measure the distance between the shock mount bolt holes and get a shock that will compress at least one inch shorter then this distance to insure you won't bottom 'em out. Now the opposite sides you'll want to measure again, but this time you're looking for the maximum amount of droop without stretching ur brake lines or having ur springs fall out. After ur springs loose contact with the frame they no longer are exerting downward pressure and hence a loss of meaningful traction. If you find you can articulate downward to the point where ur springs can easily fall out then you'll need to consider installing Limiting Straps. Once you find ur downward travel distance, you would get a shock that would extend at least one inch farther to insure that it won't get stretch too far.
You can now look up, or call, a reputable off road shock manufacture to get the correct length (up & dn) shocks or make adjustments to your articulation to accommodate the shocks that are available. Of course now you get into the realm of what kind of driving are you gonna be doing, rock crawling, road racing, highway, etc., to find the right type of valving... LOL, and you thought this was gonna be easy.
Hope this helps. And I'm sure there are more ideas, comments, out there for ur consideration.
Best, Tatt
