Sync 3 has a nav update as of May this year. Have to order through a dealer and runs about $150 + tax.
Sync 2 is regularly updated about once a year. Just an SD card swap and doesn't need ordered through a dealer. In general if you wait about 6 months after new updates come out, you can find them on Amazon or eBay for around $50 versus the direct pricing of around $150 here as well.
As komondor mentioned, generally when updated maps are released, the data is about a year old. Just the nature of these things.
If you are curious how old your current map pack is, read off the code on the SD card. A8 is the latest version for US/Canada and came out this spring and you can get an idea going backwards. A7 would have been 2017, A6 = 2016, and so on.
I'm an oddball in that I personally like using the built in nav especially on longer trips and not tying up my phone. I certainly don't go out of my way to spend tons of money to update it the moment a new version comes out but usually wait the aforementioned time for the prices to come down.
There's also apparently ways for Sync 2 nav, that I won't go into detail here for obvious reasons, that you can 'acquire' the map updates unofficially.