Has anyone skipped getting a carseat adapter and just gone with an infant insert? My youngest is 5 weeks old, and I'd love to start walking with him and the two-year-old. I have a Graco Snugride, which doesn't fit with many of the jogging/all-terrain strollers I've looked at in my price range. Plus the car seat adapters are expensive! I'd love to be able to skip that altogether. It would open up my options a lot. (Disclaimer: I know I can't jog with the little guy until he's at least 6 months.)
Re: Stroller Infant Insert vs Carseat Adapter
I also know manufactures say it's up to you since they don't want to be liable for any issues.
The car seat is good to have, but it also puts the baby in a limited seating position while you are pushing them around. Instead of letting them stretch out and lay in the stroller.
Its entirely your decision do what you think and feel comfortable with.