and have been building up hours over the last few weeks to get to the 12 hour period.
A License Proficiency Check (LPC) is generally cheaper than building a number of hours to reach the magic 12 hours (including one hour instruction). My last LPC was only 40 minutes in the air for example.
For me personally, I made the decision long ago that if I would need to do "hour building" to reach the 12 hours, then it's no longer a hobby and I should quit. Life is expensive enough without hour building.