I totally recommend managing your domain assets on your own computer, and keeping a "master" list thatโs always up-to-date.
I know it's very convenient, but relying
solely on registrars, marketplaces, or even online portfolio management solutions for your domain assets can be risky. Some recent threads about suddenly missing domains from registrar and marketplace accounts can easily be found on this forum. Glitches can happen anywhere and any time, and there might be times when you will not be able to access the Internet. Also, you might want to prepare your family and friends to manage your domain assets if you become ill or some other unexpected event happens.
As
@pb also suggested, using a free program like LibreOffice Calc, or any other spreadsheet or database program, can help you keep track of your domain assets easily.