on my normal QD routine, i use about 10 towels. these are one sided (one side has longer thread than the other).
you can get these double sided ones from griots. these are by far one of the best mf towels imho. just make sure to completely remove the tag before use, and wash it before use as well.
in the future when my one sided ones wear out (i have like 24), i will just buy more of these.
Griot's Garage 11269 Micro Fiber Spray-On Car Wash Cloth - Set of 3 : Amazon.com : Automotive