Some issues going forward:
Some day you will have to upgrade, so plan for the eventuality.
Some people believe that Apple has stopped releasing security upgrades for Snow Leopard; but I am not one of them.
However, use proper prudence: to the extent that you need to use the Internet, it would probably be best to do so on your Maverick Macs. If you must read email on this Mac, do not download any attachments on this Mac.
There are others here with more information or by a search, you can read more information about safety practices on a Mac in general and on a Snow Leopard Mac in particular.
I also used to be the first on the block to upgrade to the "latest and greatest!" Now: not so much!
I am still using Lion, forced upon me when my iMac G5 failed and I purchased a 2011 Mac Mini. Since that day, I continue to use Lion and have found no reason to upgrade.
I have installed Mavericks on an external hard drive and occasionally dual-boot to it for experimentation and experience for that day when I need to use an app (or otherwise) that will require Mavericks.
I still use Snow Leopard installed in Parallels for the occasion (growing more rare) that I must run a PowerPC app.
Good luck!