I have done this before and had success. First of all, you have to treat this as a business transaction not loaned to a friend. You can find sample contracts on the internet and you need to have one. Figure out what your replacement cost for all items rented would be. In my case that was $4000. Then get that amount in deposit, not a check but actual cash deposit. Then the rent was $400 a week. I then spent about an hour of time with the renter going over the procedures and cautions and operation of the system. Once the system is returned check it all out and go through your normal testing procedures and post-trip procedures, clean it up well. Your contract should state that you have 30 days to return the deposit less any cost for damages or cost for missing items. I did this 3 times before there was a problem and I had to keep some of the deposit. I later sold the system to the renter.