I have a (very large) spreadsheet with all my passwords. Like yours, the great bulk of them are the same, and for the same reasons. Fortunately, there aren't many people around with the same name as me, do for close to 50% I can have the same ID as well.
But it is a pain having to look up passwords (and Credit card security numbers, and all that stuff). When they insist I must change my password, I just add a number to the end or update the existing. Mostly, their software doesn't twig that twit0001 has become twit0002: some complain "new password is too similar to old password". Those, if they are selling stuff, soon lose my business.
But if you want to hack my electriity bill (and pay it, even) feel free!