I dont have a BBT. I just use a regular one, does that matter that much?
It only matters if you're unable to see a shift.
There are some BBTs that measure to the .00 and some that measure to the .0 - it's not the degree to which they show, it's the degree to which they round. BBTs can be a little more precise than regular thermometers.
If you're unable to see a shift in temperatures this cycle, then I would recommend investing in a BBT.