Far too many installs fall short of cables and few that were made "cut to fit" DIDN"T. Whats so hard about walking the distance and adding ten feet for every floor entered. Simple observations could point out trouble areas and extra lengths must be added to work around obstructions. Estimates must allow for 30% over and unforseen problems. Nothing like trying to track down some added cables on the end to finish an upgrade before their deadline.. The only cut to fit I use are the ones I do. I seldom have any left over, maybe a couple patch cords or so but the limits aren't blown away. A single pace is just three feet, is this too much to figure out. I've seen allowances at first glance were okay, but three hundred feet was estimated/quoted and a bit more than 1,000 feet was required. Nobody taught that clown to look for wall penetrations and ask about any restrictions of spaces. Ended up with three hundred feet where cabling had to be in grounded conduit, the rest was fine pulled with other cabling in the ceiling. Ever hear of "over run" insurance.