Due to having Rheumatoid Arthritis etc. I have been forced to lengthen times between washes. I do CWC with sulfate free shampoo and lots of cones. If I am lucky I wash my hair every 2 weeks but have gone as long as 7 to 8 weeks due to surgery, flaring etc. RA has taken so much from me that I refuse to let it have my hair (as in cutting it to make it easier to care for).
I usually just do a cinamon bun with a hairstick and no one but me knows when I last washed it.
I have discovered an olive oil infused hair lotion at Walgreens that is wonderful to use on my ends.