As a freelance designer you're likely to have clients and collaborators in multiple time zones. Doing the mental math to figure out what time it will be in San Francisco at a given time in, say, Yangon can be a headache and leaves room for error.
Download 'Miranda' on your iPhone or Android and make life easier for yourself. It's the most clever UI I've seen for figuring out meeting times across multiple time zones. I've already mentioned Miranda in a previous post about essential tools for freelance designers but I'm still loving it and felt the need to call it out separately. Get it from the App Store here.
Big kudos to whoever the designer is over at SoftFacade. It's a really clever and simple UI.