Best practice is to change your password regularly and as SupermanoX stated, the use of strong password is recommended. The longer the password is the better, but using combination of Upper Case Letter, Lower case, and symbols such as %,@,#,$,!. (e.g. Th3C@t!sEye$) is a good example of a strong password which reads as (TheCatsEyes).
If you cannot remember passwords well, I would recommend you to get "Password Safe" google it and download it (it is free).