Not only change your passwords, but don't use just one for everything and don't leave your passwords written anywhere.
I created my own cipher that is complicated enough that all I have to remember is something maybe as easy as 'routerpassword' but using my rules that becomes something with a mix of lowercase, uppercase, numbers, and symbols. You only need to memorize your conversions at that point and can quite easily have a different password for every device, account, and system you manage. You can even keep a list of the pre conversion passwords anywhere you like. As long as your cipher key is never ever written anywhere.
A basic example would be to make all e's into 3's, a's into 4's, s's into 5's, p's into 9's, i's into 1's, L's into !, b's into 8's (sort of a modified leet code kind of thing). Mix in a rule like the 3rd actual letter is always capitalized and you have an entry level one. Mine is nowhere near this simplistic and neither should yours, but creating your own key makes using passwords a breeze.
I can change my passwords every month and never get lost.