Outsource when measuring is the thing stopping you from bidding more. A mid-size drawing set eats a night or two out of somebody's week, and that somebody is usually the person who should be walking jobs and answering GCs. Sending the measurement out turns fixed payroll into a per-bid cost you carry only in the weeks you bid.
Order the measurement once you have numbered sheets, a stated scale and enough schedules to resolve the conditions. A single-room remodel or a two-page service order is faster to measure than to brief out, and paying anybody to do it, us included, is not a saving.
Skip it too if what you want is somebody to own the bid decision. We measure, and on the estimating desk we price. We do not choose your markup, we do not pick which invitations you chase, and we do not put a number in front of a GC with your name on it.
The test that settles it
If measuring this set would cost you an evening you cannot spare, and the drawings answer the questions an estimator would ask, outsourcing pays. If either half is false, keep this one in house and send the next one.