Yesterday was the start of the last week of free service aboard YRT and Viva. Beginning this Sunday, April 1st, the normal rules regarding fares come into effect again: You'll need to pay a fare, deposit a ticket or show a monthly pass to board a YRT vehicle (or TTC bus in the region), and have a monthly pass or a validated ticket on you as you ride Viva.
This is also the last week you'll be able to return your February monthly pass to the YRT office on High Tech Road for a refund. If you miss the deadline, though, don't worry; you can just use the pass as-is in April instead.
Finally, if you weren't riding YRT during the strike, be aware fare prices went up at the start of the year. For occasional riders the cash fare is now $3.50, but rather than pay that I strongly recommend you buy a ten-pack of tickets at the discounted price and keep a few on you while you're out. And of course, if you've enjoyed the freedom of unlimited travel on transit these past two months, a monthly pass (available now!) will let you relive the experience in April.