There are a few basic questions to ask yourself before buying a carrier. This list will provide a good starting point.
1. How old is your baby and how much does he weigh? If your baby is not newborn, will you need to use this carrier with a newborn in the future?
2. Until what age are you planning to wear your baby?
3. Do you need to use the carrier for one child, or do you need something that's easily adjustable between wearing a baby and a toddler?
4. Are you the only person using the carrier, or do you need something that's easily adjustable for different caregivers?
5. Do you need a carrier for short trips (in and out of the car), or are you planning to wear the carrier for longer periods (baby having a sleep in the carrier)?
6. Do you like the idea of wrapping or tying, or do you prefer buckles?
7. Do you have any clear colour preference?