Advise on item rentals.

In a new campain I am still thinking up I am thinking about adding in a rental system.  I am thinking of make the rentals a 10% cost of the items per 10 day (in game week).  There would be a cleaning fee of 5% and a repair of 5% (up to what mend could fix).  If the item is returned with missing charges or heavy damage a 25%-100% charge of the item.  This way people could rent items at a lower cost and maby carry some of Sh@# items.

Example 

Level 3 scroll of fireballs normally cost 200g.  You could rent it for 10 days for 20g.  If you use it you would have to pay a total of 220g. ( 10% rent and  100% item)

+2 sword would normally cost 4,000g to buy.  You could rent it for 10 days at 400g.  If returned with out cleaning or normal repair you would get charged a extra (5%+5% 400g for 800g total.

Wand of Fireballs  world normally cost 4,000g to buy.  You could rent it for 10 days at 400g.  If returned with out with out it back to full charge they would a extra (25%)  1,000g for a total of 400g. (yes it would be better to just rent it for the extra week and let it recharge but some items do not recharge.)

What do you all think?  do you think the prices would be right or will I need to change it.  

P.S.  The group renting them out will have the means to hunt down thief's and make them pay.

I have one question how are you going to enforce the system if the players just decide not to pay the fees and keep the items?