Chose your tenant very carefully.
PRC, Bangla, Filipino, multiply very easily. One will become
two, and so on. BTW, if your tenant brings in an illegal immigrant,
you can be prosecuted. Ignorance is no excuse, as an ah
pek found out.
If electricity and water inclusive, they will abuse.
If they are reluctant to mix with you, they will throw
things out of the window. Like food packets, used sanitary pad,
cotton buds, cigarette buts etc.
Be ready to kick them out, when they are in arreas. Usually
towards the end of the tenancy, they begin to delay payment, they
will skip out when they owe you three months rent.
You need firm ground rules, or renting out a room will turn
into a nightmare not worth the money.
Students, rent paid by parents are the best. Only need to watch
out for arrears, and the parents need you to watch over their
kids.