Before you do anything, do the easiest things first:
- delete the contents of the download folder
- empty the trash (including the trash in apps like iPhoto)
- in iMovie, delete the projects, and the related events from projects you have finished with, and don't let them build up...
First and foremost you need to understand that 250 Gigabytes is a LOT of space, the problem is that many, if not most teachers still fundamentally do not really understand how big a gig is.
How big is a Gig?
A kilobyte is about one page of text, a megabyte is a 1000 times bigger, about one digital photograph, and a gigabyte is a 1000 times bigger than that, like one high definition full length movie.So a Gigabyte (Gb) is a 1000 times bigger than a Megabyte (Mb), and a 1000 times smaller than a Terabyte (Tb). What? I have explained this in more detail in another post, but maybe one of these analogies will help, trying to represent everyday sizes that are 1000 times bigger as you move up the scale:
 |
| How many rice sack sized files do you need? [Click to enlarge] |
 |
| How many elephantine sized files do you need? [Click to enlarge] |
 |
| How many suitcase sized files do you need? [Click to enlarge] |
So with 250 sacks of rice/elephants/suitcases worth of storage (250 Gigabytes) on your MacBook Air to use, how can you be low on space? A few reasons:
- You transferred everything from your previous computer, chances are you need about 20% of that.
- You have loads of video hiding in your iPhoto library.
- You have load of video clogging up your iTunes Library.
- You have a load of video files languishing in folders on your Mac, maybe on your desktop, or somewhere else...
By now you may have noticed a pattern forming, the main culprit is video. If you have a recent model of smartphone it is likely (whether you realise this or not) that you are recording in 'high def', tech speak for very high quality, and there is no easy way to change this. All you need to know is that just 1 minute of video can easily be 200 Megabytes, that's 200 bags of rice, or 200 cats, or 200 carry on cases of storage space. That's insane, and yes, this will eat up your hard drive capacity faster than a Panamanian termite mandible strike.
Solutions?
Get rid of most/all of your video, if you don't want to delete it, then move it to an external hard drive* how? Well it's most likely buried in the following locations:There's probably loads of video in your iPhoto library, but how do you collate it all in one place? To view all of the video in iPhoto, create a 'smart album', instructions here, where you create an album which only shows 'photos' that are movies—yes, you're right, that does not make much sense, but it works. This will allow you to view all the video you have in iPhoto in one album, then you can either select the lot and drag it to a folder on an external hard drive, or delete it (hold down option + command, then hit the delete key).
If you're keen on buying/renting video via iTunes, or even importing video into iTunes so you can play it on an Apple TV*, get in the habit of removing it when you've watched it. My advice is not to use video in iTunes at all. Anther storage hog in iTunes are all apps stored in the iTunes folder if you sync an iOS device with your laptop, you can remove these as they're all stored in the App Store for you anyway.
Use your Time Machine back up drive (You do have one, right?) for extra storage, this can be used as a normal harddrive, just don't put anything in the database folder called 'backups.backupdb', the rest can be used as you like. In Time Machine preferences you should exclude non-essential folders from the backup process, such as Google Drive, Dropbox and the Downloads folder.
Search & Destroy
In the Finder (if you're confused by this just click on your desktop—assuming you can still see it), press Command and F to bring up a custom search, which you can tweak to focus only on file size, this is a great way to find massive files lurking in obscure parts of your hard drive:
Choose 'This Mac', change 'Kind' to 'Other', then pick File Size from the menu. Now tweak the parameters, I'd start with greater than 50 MB, right click the menu bar and choose Size from the list, click on this to sort all your files with the biggest at the top. Now start deleting. Command+delete keys are a easy way to quickly delete things, you'll still need to empty the bin when you're finished.
Use 'cloud' (online) storage instead...
Now we have more cloud storage than you can throw a thumbstick at, you can store more online—but remember that one day you will leave UWC, and when that happens you're back to 'normal' cloud storage space—'unlimited storage is only for educational (gapps) domains, not private Google accounts.If you are going to store loads of content in the cloud, eg Dropbox, Google Drive et al, you can easily find yourself with more content in the cloud than you have space for on your computer (Google Drive is 1 Terabyte now, that's a LOT of elephants) which means you won't be able to simply sync it all with your hard drive, instead you can use selective sync, to only sync the folders you choose, here's how it looks in Google Drive, similar options are available in Dropbox as well:
 |
| Files you don't have permission to edit will not be 'syncable'. |
 |
| Choose what you use, and change these to reflect your changing priorities. |
*Finally, if you're someone who absolutely NEEDS to have massive amounts of storage handy, all the time, everywhere, then maybe it's time for you to move into true nerd territory, and go for a Laptop Hard Drive Backback solution, yes, there is one, in fact there is more than one.
*Importing video into iTunes just so you can watch it on your Apple TV? No need, just download Beamer, and bypass iTunes completely, just drag and drop from anywhere, including an external hard drive; even better it plays any video file, not just the video files iTunes likes.
