You may ask yourself why Adobe Flash needs to be constantly updated, and the answer is simple. Flash a commonly used tool by malware authors to gain access to your computer. Adobe patches vulnerabilities in their Flash player as they become aware of them, so you need to make sure you apply the patches / updates as they become available as they are normally security related!
Here is the link to check if your Adobe Flash is up-to-date:
http://helpx.adobe.com/flash-player.html