Stock spring length? Do these things Ever Wear Out?

I have a had a set of Bilstein 5100 shocks (front and rear) sitting in my garage for a few months now and I want to install them this weekend. I also have a set of OME 885x coil springs for the front. And I have all of the bushings for upper and lower control arms as well as new OEM cam bolts and hardware. The only thing I don't have yet are some aftermarket upper control arms - I figured I would get SPC or JBA (either are supposed to be good).

Since I don't have the upper control arms yet and am getting anxious to install the 5100s, I thought I would just install the 5100s with the stock springs at stock height and not have to mess around with the bushings and getting an alignment done. I'll pick up the upper control arms next month and install the OME 885x coils and new bushings and get the alignment done at that time.

So, getting to the title question (sorry for the long post):
I will to measure the OEM coil length when I take the stock coilovers apart and want to compare this to what the length of a new OEM coil is supposed to be so that I can understand if I need to set the 5100s at zero or maybe set them at 0.85" or something to compensate for worn out springs. I don't know if the springs actually wear out and loose length or sag; it was just a thought I had. My Tacoma is a 2005 DCLB with around 275,000 miles (442,000 km) on it and I have been driving it for so long that I probably don't realize or didn't notice how bad the stock suspension has degraded over time (its a little bouncy and oscillates more that I would like it to).

Thanks.

 

I got the 5100s installed. My OEM springs were 14.25" long and I set the 5100s clip at the zero position. Much to my surprise, the shocks weren't totally blown or leaking oil but they sure didn't have the greatest ride anymore. Looking forward to the 5100 ride.