Q: Can you use different Apple power adapters with different laptops since they're all different and specific power requirements?
A: Ah yes, we're surprised this question hasn't come up before since we hear it all the time in and around our offices.
But let's be clear. According to Apple's FAQ, the MacBook laptops were designed so that you can use a higher wattage power adapter if needed, but going backwards is a big no-no. That is, if your current adapter is 85W, you shouldn't use a 45W adapter unless you're looking for potential operating issues.
For the curious, using a higher power adapter does not will not cause the computer to charge more quickly or otherwise operate any differently than using the adapter that came with the computer. Using the lower power adapter (not recommended), will underpower the laptop, causing strain on both the computer and charger.
We hope that helps debunk any myths out there while helping keep your laptops nice and healthy!