If you have trouble writing and replying to emails, here’s a simple trick: Set a timer for three minutes. Now write that whole email before the time runs out.

If you google “15 minute timer”, or any length of time like that, then Google will automatically open and start that timer. But it will also show you several YouTube timers of that length.

They aren’t much good as kitchen timers or productivity timers — if you try to google one up, Google’s already started a better timer for you. But they’re great for displaying a countdown to an audience, especially an audience of kids.

Moving from one activity to another can be difficult, even for adults. It’s especially challenging for kids when the transition is being made from something enjoyable (such as playing or watching TV) to something less desirable (such as leaving a fun place or doing chores).

When my son was a toddler, he had a really hard time being dropped off at and being picked up from preschool. He’d cry or physically resist leaving, refusing to get into his car seat.

Mac/iOS: Setting an alert on your iOS device or Mac computer can be done in a variety of ways. You can ask Siri, use your Clock app, set up a reminder, or make an alarm. Unfortunately, these all come with a few caveats that may leave you confused as to why your phone is buzzing at 3AM - or end up with you rushing out the door thanks to a missed reminder you thought your HomePod would share with you. Engineer Dr Drang took a look at how it all worked and found that, well, it was pretty confusing.

Mac: We've seen plenty of Pomodoro timers over the years, but Tomates might be the most full featured option around.

Mac: There are plenty of Pomodoro timers to choose from but I like apps that disappear when you don't need them -- and are a single click away when you do. With that in mind, Pomodoro Time lets you time your tasks and manage your to-do list right in your menu bar.

Time-tracking app company DeskTime found that the most productive people worked for 52 minutes straight followed by a 17 minute break. If you'd like to try this routine yourself, Fōkasu is the easiest way to time yourself.

Mac: Sometimes, you just need a quickly accessible timer. Countdown is a Mac app that does just that.

If you're looking to reduce the amount of time you spend in the shower, this DIY setup starts a timer automatically as soon as you close the door.

Android/iOS: We've talked about the benefits of interval training on a stationary bike before. Interval Clock is a customisable interval training app that will get you started quickly, help you find an effective workout, and still leave you free to switch things up as you choose.

Many people swear by the Pomodoro Technique, a strategy for sprinting through tasks to get more done, while allowing for brain-resting breaks. You don't need a Pomodoro timer to apply this -- just use regular, limited-time "real life" events for your timer.

Mac: Pomodoro timers are easy enough to find, but if you're looking for something that's incredibly simple and free, Pomodoro One does the job. It's a no-frills app, but that's kind of the point anyway.

Android: Regular timer apps typically count down in hours, minutes and seconds. Downcount keeps track of important events by displaying them in a daily countdown.

There's no shortage of to-do list apps and services out there. What NowDoThis excels at is eliminating the clutter and keeping you on track. Enter your to-do list at the start of the day, include a duration if you wish and hit Start. NowDoThis takes it from there.

Mac: The Pomodoro Technique is a great way to stay focused and on task, but to really follow through on it, you'll need a timer to match your work sessions. WorkBurst is a new Pomodoro timer that takes the clock-watching out of the equation. Work until the screen dims, then it's time for a break.

Android: Have an important date coming up, such as an anniversary or a project deadline? Days is a beautiful and simple Android app that will count down the number of days left, and show it as a widget too.

Hi Lifehacker, I've been trying to find a countdown screensaver for my exams for a while now but I just cannot seem to find a good one. Have you seen any good/cool live countdown screensavers for Windows?

Google introduced a built-in timer command last year, but then mysteriously dumped it after a few days. Now the timer is back.

Android: Using your phone to play music as you drift to sleep is great. Finding out you left the music app running for eight hours is not so great. Super Simple Sleep Timer solves this by killing or quieting your apps after a set time.