This is a regular question and complaint that we get at Experimax Avon. There are numerous reasons that we are going to take a look at just some troubleshooting options. 

The first thing to check is how much storage you have versus the amount you are using. Just click the Apple® logo on the upper left corner of your screen, choose "About this Mac®" option and pick the storage tab. In the event that your hard drive is extremely full, it might be an ideal opportunity to clear out documents you don't use. In the event that you would prefer not to erase anything other than need to clear space, you can buy an external drive and back up your machine to that. After backing it up, you can erase files off your machine without erasing them totally. You will be able to access them at a later time. 

In the event that you have a lot of storage, it is ideal to check how much memory you have. Storage is the amount you can save to your hard drive and memory is the means by which rapidly you can flip between errands. To check your memory click the Apple® logo in the upper left corner of your screen and choose "About this Mac®". The memory option will disclose to you what number of gigs you have. Depending upon what projects you are running, we recommend in any event 8 Gbs. Remember that MacBook Airs® and MacBook Pro Retinas® can't be upgraded as far as memory. 

Another option is to take a look at your dock and see what applications are open. Make sure to close applications you aren't using. 

In the event that you are still having issues, please visit us at 10665 E US Highway 36 in Avon, IN where we would be happy to further assist you.