Boiler Maintenance Recommendation

Anyone have a recommendation on someone to come take a look at my gas boiler, It’s only 4 years old so all should be well, but I’d just like to be sure. I had it bled about a year later, but nothing since then. I thought about just bleeding it myself this weekend, but I am curious to know what or who is out there to have an alternative or recommendation? Anyone used the boiler service on groupon , called a ” Good Plumber” . Thanks!