I decided not to trim until my hair goal and this was my experience:
I was about a half an inch or so away from APL yesterday and had to trim damaged ends from not trimming since September 7th. I spent three months gaining almost 2 inches just to have to cut off 3 inches last night. Basically I had to chop an in of hair in the back for every month I neglected to dust/trim. My hair just feels healthier when I'm not forcing it to last without trims. I am totally going back to trimming 1/4 in. every 2 months.
Cons I Experienced:
My hair would ALWAYS get caught on the comb
I would lose a lot of hair just trying to detangle
I experienced more tangles when I combed my straightened hair
My straightened hair was stiff and had no body
My ends would clump together in an unsightly way and just sit there
The ends would not get straight and lay flat, but rather they were dull and feathered out
My hair would NOT hold a curl, bump, flip,... anything!
My hair was "long" by some peoples' standards... but raggedy by everyone's standards
Pros I Experienced:
My hair was longer, despite its bad health
I didn't have to go through the process of washing, conditioning, drying, straightening, and holding up my hair to trim all my ends
I had that funny looking "tail" on the back of my hair
My bangs grew out a lot