So much this! I have multiple business entities that all use separate accounts on many different services. I use the Window Titler extension and different windows for each business entity. This is the only way I can keep them all straight and it makes switching roles so easy. I just wish Firefox allowed me to Move Tab to a specific already opened window - seems like such a simple addition.

Unfortunately one of the services doesn't function properly on Firefox and so I have a constant nightmare of sign-in / sign-out / disable automatic sign-in (that somehow get auto checked) on de-googled Chrome.