I tune my own melodicas and wouldn’t pay anyone else to do it because (1) it’s not that hard and doesn’t require a very demanding skill set, and (2) my results are satisfactory in relation to my own expectations. I know some others here tune to a higher standard and have the skills to do so. The typical tuning issue, is a few notes that are noticeably off, and that’s easy to deal with. It is also satisfying to do one’s own tuning and develops a better feel for the instrument. Meaningful tuning for me requires taking the melodica and putting it back together again at lest 4-5 times. Retuning to, say, 440 from 443 is a bigger job, which takes me a day or two of multiple tuning sessions.