For me, i would analyse calmly before deciding on it. Factors affecting whether i should lend or not depend on the below
1) Does he take good care of things. If yes, to what extent. Treasure it and ensure scratch-free?
2) Does he/she knows how to use a DSLR to his/her advantage.
3) How close is he/she to me?
4) Is he/she automatic kinda person who will return without asking?
5) It also depends on the current cost of equipment i am holding now, too ex, i won't want to lend either.
If in the end borrowed to him/her, i will still inform him/her the cost of my equipment and he/she has to pay for any damage incurred especially if its a big sum. (Above $500 repair or getting a replacement)