6 csr's, 4 quarters/year...means that I'll get a new plaque at least once a year.
My guess is one plaque per CSR is all they would ever need (want). Racking them up is just taking up valuable space (in cube, at home). Maybe change up to quarterly with annual reward/plaque? How much is the plaque? $25? So give 'em $75/quarter and ix-nay the plaque. Do an annual plaque, keep it in the office, and make it one where you can add a new namplate annually, and bump up the annual award to $100 or more.
On retention, I'd level the playing field. Maybe make it monthly...and the winner is the one who retained for the largest annual premium. Or add up all the retained premiums, and award accordingly per time period (montly, quarterly, annually, i.e., Joe retained $9,000 this period, Sue retained $7500, etc.
For "in a rut" I would inject as much lighthearted 'competition' as possible, taking care that it doesn't get out of hand. Best Pet Name of the week. Best Owner Name of the week. Best rejection of the week. Best Fraud Attempt of the week...whatever.
You could also do things like publish stats: everyone's name on a board with # new sales today, # retained, # by pet (4 dogs and 3 cats). Seeing your name with numbers attached, as compared to others, does something psychologically. Helps keep focus...eye on the prize sort of a thing.