Love tmux. I don't find myself splitting one window into panes very often, but I certainly use multiple "tabs" (windows) in a tmux session. I keep a tmux session running on my work computer, which has logins to all my commonly needed systems. I can ssh in from home (or anywhere), attach to that tmux session, and instantly have everything I need.
Other answers tell you how to attach, but vital missing piece is that beforehand, don't "quit"/"exit" the session but "detach" from it instead, so you can attach later. By default the command is $PREFIX + D
