Do I need a rebuild every time I make changes to my bubble app?

No.

You do not need a rebuild for any changes made to your bubble app.
Changes to your bubble app flow directly inside your native app, just like they do on a web browser
Infact, your app users won't even require to update their app from appstore / playstore to see these bubble changes. Its' just like in the mobile browser

A rebuild is required only when
You want to change some information that you've submitted in the BDK Native Project form, such as your App Icon
You want to upgrade your app's bdk native engine version, to take advantage of some new features we released after your app was built

We are constantly making improvements to BDK Native Engine by adding new features and speed improvements. To see a history of releases, please click here

Updated on: 12/04/2019