Why does this software update so frequently? It seems like monthly. Is it necessary to update whenever they prompt?
Its a program that enables playing videos and taking “instructions” from other programs. Its known as a potential vulnerabilty for viruses and rogue scripts, and has to be kept up to date when new vulnerabilities are discovered.
That said, make sure you update by going to the adobe site to update your flash player. There are lots of fake update sites that intend to give you something more than what you want. A lot of the “your flash player is out of date” messages are not legitimate.
If you update from the popup window, is that legit?
LOL, looking at the title of the I thought Adobe was hacked to display what a flasher would. 
Sometimes its legit, but if you can’t tell for sure on your own, just go to the adobe site.
https://get.adobe.com/flashplayer/
The pop up windows often come up from malicious sites when you click on some video (not necessarily that kind 
) But they can arise from seemingly innocuous sites. And sites that relate to the hot news story of the day i.e. see “Justin Bieber disrespect Taylor Swift at last nights concert”.
In any case, I never update flash player from a pop up. I guess if you have the flash player set to update whenever they do it, you’ll get lots of updates, but I just have the notify me before any update feature set, and then I go to the site and do it on my own.