Having tried both strategies, unless your task is brain-dead simple and/or you have a way to cheaply and deterministically validate the labels, always pay to retain the team.

Even if you can afford only a couple of people a month and it takes 5x as long, do it. It's much eaiser to deal with high quality data than to firefight large quantities of slop. Your annotators will get faster and more accurate over time. And don't underestimate the time it takes to review thousands of labels. Even if you get results l in 5 hours, someone has to check if it's any good. You might find that your bottleneck is the review process. Most shops can implement a QA layer for you, but not requesting it upfront is a trap for young players.