If your Mac is using the latest applications, chances are that your machine may become slow over time. If the delays on opening new apps, trying to work online or simply playing a video on your Mac is becoming a pain, you may have thought about the price of a new machine and cringed.
You do not need to do it.
Instead of shelling out a couple grand on a beautiful new Mac, and you're handy with a screwdriver, you can simply upgrade the RAM in your machine or pay a professional if you're not confident.
First the bad news. If you have a MacBook Air, you will not be able to upgrade RAM. It's soldered onto the logic board and I would advise against it. (Breaking your MacBook Air defeats the purpose of trying to speed it up.)
Unibody MacBook: Remove the bottom cover to gain access to the RAM.
MacBook: If you have an older model MacBook, the RAM in these machines are located adjacent to the battery. Remove the battery and the memory door and pull on those little levers to gain access to the RAM.
Unibody MacBook Pro: Take off the bottom cover, disconnect the battery and unlock the RAM tabs.
MacBook Pro: Just take out the battery, the screws and memory door. Behold the RAM!
Mac Pro: Take off the side cover, slide out the riser cards or tray. On older models, you will need to install RAM in matched pairs. Check your manual first.
Mac Mini: These machines a bit tricky to get open. Insert a putty knife in between the lower and upper case to open the box. Take off internal frame to gain access to the RAM.
Intel Mac: Take out the screws on the bottom of the machine and flip the lever to remove the old RAM. In its place, insert the new RAM.
Hope this helps!