Many popular sites still require Flash. Hulu, Crunchyroll, HBO, etc etc. If those sites or similar are important to you will need Flash in one form or another.
Probably the most secure thing to do would be like some suggested uninstall Flash and use Chrome however I would append that by saying use Chrome specifically for using trusted Flash sites then close it when you are done. Use a different browser for your normal web browsing or disable the Flash plugin in Chrome if its your preferred browser. Chromes flash plugin isn't invulnerable to Flash related maliciousness.
I prefer Safari so I just do what you use to except I block Flash unless its a trusted site. When I visit a site that wants to use it and I know I need it (again many streaming services) I check for an update directly from system preferences (NEVER follow online links), update if required, then trust website if I visit it often.
If what you are doing now doesn't end up working for you I would just try reinstalling it fresh from Adobe instead of updating it.