Having a good Antivirus is just one part of keeping your system safe.
I too have some old software that I regularly use that won't make the move/transition to win10 and for that reason I was hanging back.
I also take lots of proactive measures, not to mention using DropMyRights on all internet facing applications, so if I do get hit it limits the potential damage.
However, plan for the worst and hope for the best, for me that is having a robust backup and recovery strategy. That is in my case Hard Drive Imaging software, making a full exact image backup of your disk, partition, etc. every week and keeping the last 6 weekly backups. I also do daily backups of volatile data files, .doc, .xls, emails, bookmarks, images, etc. etc.
My drive imaging program is also one of the very old programs that wouldn't the move to win10 and it has saved my backside on numerous occasions, not one being related to virus infection. Much of the new disk imaging software should work on win7 (making it possible it would also work on win10) and that can also do incremental backups not just full backups.
I have been using avast free for over 13 years from early 2004 on avast 4.x