With the default printhead, the nozzle should be easy to exchange without removing the hotend - it is exposed enough. That said, removing the hotend is one grub screw and one plug - so getting out the hotend is really simple. It gets even simpler with the dual extruder head - it is one lever press.
Unless you use filament that is highly abrasive or has a strong tendency for clogging/debris, I would not see too much need to regularly replace the nozzle, but this comes from a low-volume printing user.