Persistent bathroom smells usually come from poor drainage, leaking pipes, or bad venting. Renovation gives you access to areas you normally can’t reach. This is the best time to fix the root cause instead of masking it with air fresheners.
Ask the plumber to check drain traps, pipe connections, and vent pipes. Proper sealing and correct slope also prevent water from sitting in the pipes. A renovated bathroom should smell fresh naturally, not only after cleaning.