When you're in Cura and you press the "slice" tab, the box that says "save to device" pops up. It shows how long in hours and minutes the print will take, and in smaller font below, it shows in metres how much filament will be used. So I suppose you could just pull the filament off the spool and measure how much you have left. Although even if you didn't have enough, as long as you had a new spool of the same, you could just monitor the progress and when one spool runs out, you could just start the new spool right behind it. Another option would be to wait until the spool only has a few centimeters left, hit the pause button on your printer, pull the remaining piece out and feed in the new spool and hit print to start it back up. this is actually the process I use for printing parts where I want to use more that 1 colour
In Cura 3.4.1, I don't recall it shows how much filament needed.
I forgot about the Pause option while printing. I'll use that when it comes to that.
Correction : Under the place where it shows time required to print, it also shows how much filament needed, although it does not help me to know if I have enough. Not unless I unroll the spool and measure with a tape. LOL.