The terminal program
xfce4-terminal has an option
MiscAlwaysShowTabs to even show a tab if there is only one shell window open. The reason is to prevent window resizing when the number of open shell windows changes between one and two or back.
Yet the tab bar contains hardly a wealth of information and I would not mind getting rid of it completely, i.e. to never show it, even if I then have to guess how many tabs are open.