Maybe this will help you decide:
-presuming, you will be taking baby on rides & to shows: Are you able to hold baby for 20-40 min. in the line ? (I know I'm done around 15 min.) Around 7mth baby may be at the crawling stage, but not standing. As well, baby could be a little wiggly & want to get down out of your arms.
I agree with the other poster to see if baby even likes the carrier before you go. Plus, yourself since there are so many styles & it takes practice.
I personally have 3 carriers & at 7mths, used them all (Ergo-still use now, Baby jorn Sport - I couldn't wear this all day/baby over 13lbs, Infantino wrap with buckle waist -great for newborns & froggie style. Is a pain to put on if ground is dirty or wet. As well, it will depends on your body shape & how comfortable baby is with leg position i.e. ergo carrier-baby's legs go on each hip & can baby spread legs that wide yet ~6mths).
As well, depending the ride, I think you can keep baby in them if they fall asleep.
We will be taking a 20 mth old & I will be taking my Ergo incase fussy at nap time / to avoid having to take baby out of stoller asleep for the bus.