When to switch to Booster full time

So my dd has been part time in a Vivo since 4 not really too much just once in a while or riding with others and could not get the GN. Most of the time its been to town and back so about 30 mins round trip. Since she has turned 5 last month she has been on hour long drives one way and was fine both times.
This past weekend we took a 7 hour trip one way 2 hrs while it was just me and her she used the GN the weather got really bad and the road conditions were awful. We get to my grandmas house to pick her up and she needed me to move the GN as its was in the middle and she could not see out the back window, dd begged to sit in her Vivo ( I brought it in case she wanted to ride with my mom when we got to town) I told her the rules like I always do and if she messed around she would go in the GN. We drove for a few hours stopped got out and ate. Got back on the road for another 2 to 2 and half hours. She fell asleep for the last hour of the trip and stayed in perfect position. She did ride in the Vivo around town and was fine. On the way home Sunday Vivo for 4 and half hours with one stop did fine. The last few hours ride only with me GN.

Normally when ridding with me around town shes in the GN
Should I switch her to Vivo full time and keep the GN until she out grows the harness just in case? Should I leave in the car installed for in town trips or not? If somthing happens both my seats would be in the car that wouldn't be good.

So she's five, over forty pounds, and can consistently use the booster properly? I'd say it's a parental choice at this point.

Sounds to me like you have two great seats. How convenient!

DS is booster training now. I told him he could go full time when he turns 6yo - next October. But I will probably let him start 1st grade in one.

I'm in a similar situation. I have a child who turned five in Feb; I "booster trained" him to find that um, he was perfect. He might be the best booster rider I have... constantly yelling at the older kids to stay in position, but he doesn't move. He had a lovely GN that I had just (and I mean within two weeks earlier) repurchased to replace his crashed one, and in the end I opted to keep him in the GN most of the time. For me, it's easier to keep him in the GN (he can buckle himself in, which he can't do in the booster,) but at the end of the summer he'll move to a booster full-time.

I would say do whichever is easier and preferred by both of you. As long as she rides well in the Vivo, then she's equally safe in either.