FWIW, while we're planning on keeping DD RF as long as possible, we are still looking forward to her turning one year old so that it will at least be "legal" to turn her FF occasionally.
We have her seat in our "family car" and we're unable to take "family trips", because in order to fit her seat (Radian -- narrow but verrrry tall) in RF, the front passenger sit is moved all the way forward.
With both DH and I being Very Tall People, it means it is EXCRUCIATINGLY uncomfortable for either of us to sit there. Thus, we can't go on long car trips with all of us (ie, someone needing to be in the front passenger seat).
I'm sure it's not all that safe for me to be squished up against the front airbag like that either, so it's not ONLY a comfort issue.
So our plan is that once she's a year old, we will turn her seat to FF if/when we go on any family junkets, then turn it back RF otherwise (most of the time it's just me shuttling the kids around). It doesn't have to be all-or-nothing one-or-the-other. The seat is easy enough to install/uninstall/reinstall.