iTunes and iPhoto: In iTunes and iPhoto, go into the programs' preferences to change sidebar text size. In iTunes' General preferences, select Use large text for list views. And in iPhoto's Appearance preferences, choose Source Text > Large. (The two iPhoto text options available are 'Large' and 'Small', though I'd call them 'Medium' and 'Tiny'.)
The Finder: To change the size of items in the Finder's sidebar, open System Preferences, and then click the General icon. In the 'Sidebar icon size' setting, you can choose 'Small', 'Medium', or 'Large'. This setting affects not only the Finder's icons, but also the size of the associated text. Curiously, though this setting changes the same items in the sidebar in Apple's Mail, it doesn't affect other Apple apps.
Bigger fonts in Mail and Messages
Other apps offer font and size settings too. Apple's Mail has a slew of options in its Fonts & Colors preference pane (Mail > Preferences > Fonts & Colors). You can choose a different font and size for the message list, and for messages, as well as for any fixed-width text.
Apple's Messages lets you change the font and size for incoming and outgoing messages independently. Go to Messages > Preferences, click Messages, and then click the Set Font button next to each of the two background color sections.
In System Preferences' Accessibility pane, you can turn on zooming that affects your entire display. Click the Zoom icon in the sidebar of that preference pane, and check either or both Use keyboard shortcuts to zoom and Use scroll gesture with modifier keys to zoom. I often use the scrolling option--which, on a trackpad, is a two-finger drag--to get a closer look at things that I can't zoom any other way, such as text in graphics on webpages.
Finally, if you have a Mac that permits you to change the display resolution, you might want to go that route. The Displays preference pane of System Preferences lets you scale your display. Try it and see if you can see enough on your screen after magnifying its scale. This alteration changes the number of pixels on the screen and, therefore, the size of text in the menubar, menu items, and so on.
Although font size settings are limited to certain apps, it's good to know where you can make this change. Set up your most-used apps appropriately, and your eyes will thank you for making them work a bit less.
This story, "Stop squinting: Make text bigger in OS X" was originally published by Macworld.