@hermit76 We started with a convertible seat the first time, and I have no regrets. We will be doing the same with the next baby.
Your context in comparison with mine in case it helps:
I live in the Appalachian South, so the weather can get pretty hot in the summer and pretty cold in the winter, but it rarely gets extreme.
I live in the northeast, so the weather occasionally gets pretty hot in the summer and often gets pretty cold in the winter, but our car has air conditioning and heat, and we dress him appropriately. Even with a late fall baby (so newborn in the winter) and no garage, the weather wasn't a problem.
Our stroller will be a Bugaboo Fox 5, with the intent of taking the baby out of the car seat to use the stroller.
We used a bassinet with our stroller for the first few months until we switched to using the stroller seat. Transferring him between the stroller and the car was not a problem. We also used a (babywearing) carrier for shorter trips.
We won’t travel much. We may have a short 2-3 hour road trip in December, but otherwise, we don’t plan to travel much for a long while.
We don't travel much either, and we haven't flown with our toddler yet. Road trips (we've driven up to 6 hours) with him haven't been much of a problem, and my friends who've taken babies on road trips have said their babies were happier in convertible seats than they were in infant seats.
I will be a SAHM, and our parents live far away, so I’m not worried about getting them bases for their cars/trading off like many parents do.
My parents live close by, but they rarely drive our baby anywhere. When they have, we've just moved our car seat to their car. It's not a huge deal to do that every once in a while, but I just bought a cheap, lightweight convertible seat for them to keep in their car in case there are situations where moving our car seat would be inconvenient.
For anyone who regularly uses multiple cars, they would have to figure that part out eventually anyway because kids can only stay in infant car seats for so long.