This very much depends on your market. Take selling services to nuclear plants compared to selling office services. While there are just 11 nuclear plants in the UK there are around 5.2 million offices: that’s quite some difference. It’s worth considering that the best agents may well not be that bothered about exclusivity: they are confident enough about delivering anyway.  If it does seem appropriate to offer exclusive sales areas you should ensure that sales targets must be met for this benefit to continue: the last thing you want is a passive agent ruling part of your roost.