My 4.5 y/o asked if he could have his seat facing 'backwards' like his 18month old sister. He said it looks cooler that way
I actually turned him FF'ing at 13months b/c I wasn't educated at the time on ERF...and held off turning him back to RF'ing around age 2 when I learned more (thinking he'd never go for it, it was too late, etc). He is still only 35lbs and didn't reach 33 lbs until around age 3.5-4, so we could've gotten more RF time in the BLVD (33lb weight max although DS is long torso'd so I think we could've gotten to 2.5ish with RF'ing him).
So, for anyone who turned their child FF and still could turn their child back to RF (by weight/height), go for it. You may be surprised!!
And on a side note, part of the reason I switched him to FF was b/c he'd throw a fit when getting into his seat and I thought it would help to be FF. Apparently (having now had another child), this is typical as toddlers assert that independence and they may fuss whether FF or RF...better to have them safer