If you follow the news you will know that over the past few months security has been a hot topic. Quite a few high profile web services have been hacked & customer info has been accessed/leaked.
Please just do yourself a favour and use a password manager. I personally use 1Password & can highly recommend it, but there is also LastPass that gets some good recommendations. It does not matter which password manager you use as long as you are using one. If you are using the same password for multiple things, you REALLY SHOULD STOP THAT.
The argument of “Oh it will take too long to setup, I don’t have time” will only last so long. What will happen if you get hacked then have to spend even longer dealing with your bank, credit card supplier, explaining to colleagues why you can’t access email & the online store where an order was fraudulently placed using your details.
Just spend the time now. Reduce your vulnerability. Use a password manager.