Can I use different power adapters to charge my Mac?

Different power adapters that come with different Macs distribute different levels of power, and as such might not be adequate for your Mac, though will not cause any problems.

For example, you may have a 15" MacBook Pro and need to use a colleagues charger they are using for their 13". A 15" has a 87W adapter, compared to the 13" using a 61W. This will mean less power output, which if you are using your Mac heavily, this may not be sufficient, and may even see your battery draining while on charge. This is a good thing to check if you are having charging issues.