Reminders is a To Do-list program. It not only records your life’s little tasks, but also reminds you about them when the time comes. On a laptop, Reminders can even remind you about something based on where you are, just as it does on the iPhone. For example, when you arrive home each day, it can remind you to feed your cats—or when you leave your vacation house, it can ask you if you’ve turned off the gas burners.
If you have an iCloud account, your reminders sync across all your gadgets. Create or check off a task on your iPhone, and you’ll also find it created or checked off on your Mac, iPhone, iPad, iPod Touch, or PC. (Yes, PC. See www.apple.com/icloud/setup/pc.html).
The syncing business also explains why the location feature is useful even if you have a desktop Mac that doesn’t move around a lot. You can program a reminder on your Mac—and your phone or tablet will alert you when you move into or away from a specified place.
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If you have an iPhone—oh, wow. Siri and Reminders are a match made in heaven. “Remind me to file the Jenkins report when I get to work.” “Remind me to set the TiVo for tonight at 8.” “Remind me about Timmy’s soccer game a week from Saturday.” “Add waffles to my Groceries list.” Speech recognition rocks when it comes to leaving notes for yourself. And iCloud will take care of copying those reminders to your Mac.
Once you’ve opened Reminders (Figure 19-28), you record a new task by clicking the 
button in the upper right, or choose File→New Reminder (⌘-N). A new blank line appears in your list. Type your reminder.
Later, as you go through life completing tasks, click the checkbox next to each one. Doing that makes the item seem to disappear—but in fact, it whips into a separate list called Completed (the top of the list, shown in Figure 19-28).
Figure 19-28. To open the Details pane, double-click the reminder item in the list, or click the 
button to its right. To close the pane, click Done or click anywhere else in Reminders.
If you click an item’s 
button, you open the Details bubble. See Figure 19-28.
Here are the options you’ll find:
On a Day. Reminders can remind you at a certain time on a certain date. In the Details bubble, next to “remind me,” turn on On a Day. The proposed time is the next “o’clock”—if it’s 12:15 now, the app suggests 1:00. But you can click the date to open a clickable mini-calendar (to change the date), or click the digits of the time to edit them.
At a location. If you turn on this checkbox, your Mac or phone will use its location circuits to remind you of this item when you arrive at a certain place or leave a certain place. (Your laptop will remind you, if it’s turned on and within a WiFi hotspot. But more often, this option will be useful if you have an iPhone or iPad that’s on the same iCloud account. Record the reminder on your Mac—receive the reminder on your phone.)
The little pop-up menu here proposes Current Location—wherever you are at the moment. That’s handy if, for example, you’re dropping off your dry cleaning and want to remember to pick it up the next time you’re driving by.
But you can click that line to specify Home (your home address, as you’ve set it up in Contacts). You can also start typing any city name, or the name of any person in your Contacts whose address you’ve specified. You’ll even see “Porky Pig Home” and “Porky Pig Work,” if Porky has a couple of addresses on file.
The final step here is to click either Leaving or Arriving. Later, your gadgets will remind you at the appointed time, or as you approach (or leave) the appointed address. It’s fairly mind-blowing the first few times it happens.
Repeat. Reminders can remind you about things that recur in your life, like quarterly tax payments, haircuts, and anniversaries. Click Repeat if you want this reminder to appear every day, week, two weeks, month, or year. (This option appears only if you’ve turned on the On a Day option.)
Priority. Click this pop-up menu to specify whether this item has High, Medium, or Low priority—or None. You’ll see one, two, or three exclamation marks (!!!) next to each item in your Reminders list, indicating its urgency. In some of the calendar programs that sync with Reminders, you can sort your task list by priority.
Notes. Here’s a handy place where you can record freehand notes about this item: an address, a phone number, details of any kind.
Click Done to close the Details bubble and record your changes.
As you now know, Reminders can give you warnings of upcoming deadlines and to-do items. You don’t have to wait until it gives you a reminder, though. Click Scheduled at the top of the list to review a list of all upcoming reminders.
Handily enough, you can create more than one to-do list, each with its own name: a Groceries list, Kids’ Chores, a running tally of expenses, and so on. Here’s a great way to log what you eat if you’re on a diet, or to keep a list of movies people recommend.
If you share an iCloud account with another family member, you might create a different Reminder list for each person. (Of course, now you run the risk that your spouse might sneakily add items to your to-do list!)
If you have an Exchange account, one of your lists can be synced to your corporate Tasks list. It doesn’t offer all the features of the other lists in Reminders, but at least it’s kept tidy and separate. (Just set up your Exchange account in System Preferences→Internet Accounts.)
The list of lists is at the left side of Reminders; it’s visible in Figure 19-28.
At the outset, the list of lists lists only one list: Reminders. But you can create others. Click the button at the bottom-left corner, or choose File→New List. (If you have more than one online account set up, like an iCloud account and a Yahoo account, you’ll then have to specify which account gets this list).
In any case, you’ve just made a new list called New List. Type to rename it to “Groceries list,” “Movies list,” whatever you like. (You can also get rid of a list by clicking it and then pressing the Delete key.)
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You can view the contents of more than one list simultaneously. Just Shift-click the names of the lists you want in the left column; the right-side pane displays a unified, combined list of all their contents.
You can also open a list into a window of its own, just by double-clicking its name in the left column.
Once you’ve created some lists, you have two ways to switch among them:
You can assign a task to a different list by dragging it. Click any blank part of its line (not the text itself), and drag carefully onto the name of a different list in the List list at left.
Once you’ve set up a few reminders in Reminders, you’ll marvel as it gracefully integrates with the Notification Center when it wants your attention.
But the real power of Reminders becomes apparent when you see it auto-synchronize your to-do lists across other gadgets, like iPhones, iPads, iPod Touches, other Macs, and even Windows PCs.
To give it permission for that kind of sharing, open System Preferences→iCloud and turn on the Reminders checkbox.
Note, however, that Reminders can also coordinate with the to-do list features of Exchange and so-called CalDAV services (Yahoo is one). To set them up, open System Preferences→Internet Accounts. Click the account you want (like Exchange or Yahoo); finally, turn the Reminders switch On.
That should do it. Now your to-do lists are synced, both ways.
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You can also export your lists as .ics files, which you can then import into Google Calendar or another program. Just click the list and then choose File→Export. You can also import an existing .ics file (from another computer, for example) into a Reminders list you’ve selected: It’s File→Import, of course.