Do I need to replace the blades?
If you're considering replacing the blades, first consider that there is an adjustment on the right (bottle) side of the machine. For BP555e series machines, you'll need to remove the side cover to make this adjustment.
The adjustment 'angles' the lower blade relative to the upper/front blade. These blades do not necessarily cut the tape because they are 'sharp'. While new blades are sharp, the machine is designed to cut with a shearing action. By angling the lower blade so that there is a slight (~1/64th) gap on the left (key pad) side of the blade, this aims to properly shear the tape.
If you make this adjustment, we also recommend cleaning any build up from the blades. A window scraper, a #2 Philips screw driver, a paper towels, and some lighter fluid are all you should need to properly clean/adjust your blades.