Two months of quiet practice in the storeroom, always timed for when she wasn't home, an old harmonium he'd genuinely never touched before this. Overheard him once by accident, and honestly, it sounded pretty rough back then, lots of wrong notes, restarts, frustrated sighs.
Kept it a complete secret the whole time. On their anniversary, right in the middle of dinner, he pulled out the harmonium and just started playing her favorite song, slightly off-key still, but clearly recognizable.
She teared up almost immediately, didn't say much, just sat there listening. He, weirdly, looked more nervous than proud through the whole thing, glancing at her the entire time like he was still waiting to see if it landed right.