My personal opinion is basically any changes made to programming should be made only if needed as a response to where you are currently at in your development - assuming a change is even necessary. I'm a fan of keeping things simple and often times it's not necessary to change things though.
Some instances where changing would be ideal:
An example: A lifter who has not been lifting that long but he is able to make progress on a consistent basis adding weight and training and recovering before his next training bout (linear progression). Eventually once he reaches the intermediate stage he isn't going to be able to make optimal progress doing this. A change would be ideal / necessary here, he would need to drop linear progression and periodize training instead.
Another example: An intermediate lifter who has already periodized his training is making progress but he's approaching the advanced stage. He would probably benefit from increasing workload over time (maybe adding an additional set for each movement at the same intensities every year or something like that). He might have to incorporate other techniques to make this sustainable (scheduled deloads for example). He might also find that other periodiziation techniques would be more suitable at this stage (example: using non-linear peridoziation instead of linear peridiozation in advanced lifters)
You have to ask yourself why the plateau is occurring - is your current training no longer sustainable or optimal for where you are at in your development, or maybe you aren't plateauing but you are just at a point where progress is slow. The former would benefit from making calculated changes to programming, but the latter just needs patience more than anything else. Distinguishing between the two is a challenge for me as well but just reminding oneself to be patient because shit takes time once you are approaching the advanced stage is good policy.
I would certainly suggest keeping core lift selection steady no matter what other changes you make though. Eventually this will pay off big time.