Of course, I had carfully calculated that there was enough material on the spool before starting the job. 
As long as you have another spool you should be fine. Practice changing spools mid print and you will find that this is not a problem, simply pause and change the spool and then restart printing.
Make sure you move the head quickly after you have paused it to stop oozing on to your print and try and pause the print in the infill area rather than when it is printing perimeters.
My print software estimations suck. Hehe. I get quotes on 2 hours print time with 74 inches of filament only to get 4.5 hours print time and 115inches etc. So annoying .
@Joshua_Taylor
what slicer software are you using?
It’s the Cura Slicer I believe.
@Joshua_Taylor Really? I know Cura is slightly off, but that much? Your printer doesn’t look like one of the Ultimaker’s, so maybe it’s because it’s a third party printer. However, I don’t see how it is that off. But, the slicer doesn’t know about your jerk and acceleration settings, so check them to see if they’re normal or ridiculously slow. Still it shouldn’t have that much of an impact…
It’s a @LulzBot printer, so I’m presuming you’re using LulzBot’s version of Cura.
@Justin_Nesselrotte It is a LulzBot, but I am using the latest version of Cura, not LulzBot’s. My part is a spacer for a jig, and it would still have worked even if a little short, so I left it printing overnight. Was happy when I cam back to this in the morning! 