QR codes for church bulletins that don't go stale
Bulletins get reprinted weekly, but the sermon notes, giving page, and sign-up sheets shouldn't need a new code every time.
Why bulletins need a dynamic code
A weekly bulletin is reprinted often, but the link on it usually points at something that changes just as often: this week's sermon notes, a giving page, or a volunteer sign-up. A static code would need to be redrawn every week. A dynamic code keeps the same printed pattern and you just update where it points.
One code, several jobs
Many churches print one QR code on the back page and re-point it through the week: sermon notes on Sunday, a small-group sign-up on Tuesday, next week's event page by Friday. The congregation learns that scanning the bulletin always shows something current.
Giving and sign-ups separately
If giving is important, give it its own permanent code so it's easy to find and never mixed up with a rotating link. Use a second dynamic code for whatever changes week to week.
Print details
Bulletins are read up close, so a 2 cm code with a short caption ('Scan for today's notes') is enough. Test the print in the light of the sanctuary, not just the office, since stage lighting can wash out contrast.