Zach,
What we recommend is at most only having one high end mic to use as a reference mic. This mic stays in the shop or seldom leaves its case. For the bulk of your measurement needs a low cost measurement mic is ideal, for all of the reasons indicated by previous posters. But also because measurement mics are often placed in harms way and are put at risk of being damaged each time they are used. If your mic stand is knocked over and your mic is driven in to the floor capsule first, would you prefer it was an inexpensive mic that you could easily replace, or an expensive mic?
-Adam