Lab/testing time

I'm putting together a justication for additional lab equipment and personnel, and would be interested what an average network engineering group spends in terms of budget and personnel on a lab and people to run it, as a percentage of overall budget. This would be primarily for main-stream issues (software testing, configuration testing), as opposed to new-vendor/bleeding-edge lab work. I'm also interested if there are significant variations between these costs with various vendors. Are the lab/testing costs significantly different if I were primarily using vendor X vs. vendor Y, and how would costs for a pure X vendor network compare to a X+Y multivendor network? Thanks. Pete.