When do I need to submit new version to Google Play

Hi! My app is up on the Android store. I’m tinkering with it and making some changes, mostly small cosmetic changes, which I am pushing live. However, I want to make a bigger change which will combine two of the main screens into one screen. The app functionality is pretty much the same, the App icon & description is the same. Do I need to have the app re-wrapped and re-submit? Is there some cutoff that makes a change material enough to require resubmission (like, if I change a screen’s background colour is that ok)?

Don’t want to run afoul of Google but also don’t want to shell out every time I make a bigger change.