I want some sort of compensation for my roommate using my switch
What do you expect the compensation to be for using your switch?
I'd like her to buy me a new switch before I need to leave on a trip.
Loaning your switch to your friend should come with no strings attached, and asking her for monetary compensation is wrong. Lend your things only out of the goodness of your heart.
I guess it's a matter of opinion, and I disagree with what you're saying.
It is unfair to expect compensation after having lent out your things. Perhaps you should have discussed your expectation for compensation before you loaned the switch.