What is the requirement for a evaluation report upon retiring?

It is the retiree's choice.

I would opt for an evaluation if it will be favorable.

Not required, unless requested by RATER, SENIOR RATER, ***OR*** RATED SOLDIER.
Reference: AR 623-205 para 3-30b, 4-4b, 5-8f, and Table 3-10, rule 10.

According to AR 623-3 and DA PAM 623-3, a retiree is not require to receive an evaluation unless they elect to get one.

Retiring Soldier's option, except in some unique situations where the Rater or S/R elect to do one.
I would guide that it get done, on the off chance the SM comes back into service. You never know...

A good FitRep to close out a career is nice, it an also add to a resume. Never wrote any on mine, my RS always told me they wrote themselves. Semper Fi.

i would think that it be neccarsay, just like if you transfered units, as for retirement i recieved none as well as retirement award 31 years because my reserve medical unit wanted me to write it, thats the problem, it may not be rs wide, this may have been a local problem but sm's do not write their own evaluations nor do they write their own awards and i will not do other peoples jobs just to inflate my ego or get another pretty ribbon on my chest

Doing a close the record NCOER isn't a bad idea, especially if there is a chance the Soldier could come back. We actually had this happen. Retired as a SSG, then came back in a year later

Why would you care?