My goal is to get bigger and stronger and have been going to the gym for the last 2 years or so.
I have definitely made gains, particularly in the last few months where I have been more consistent. However it never occured to me that having a program in place would be useful, usually i just determine which muscle groups I will do on each day and go into the gym with the goal to destroy the muscle split selected.
Im sure there will be some bias as I am talking to a forum for free training programs but, is it necessary and how will it really benefit me?
No it's not "necessary"; it just makes it easier. If you have a regular routine, you don't have to think. If you find yourself in the gym not knowing what you should do next, then maybe a routine would be beneficial. On the same note; finding the "right" routine can be exhausting. If you really are looking for a routine; find one you like and stick with it. Stop looking for new routines after that. You should give any routine 1 year. After that, you can look for a new one; if it's not working for you...