Really no more than the typical hydraulic cam these days.
Periodic lash checks is all that's required. As long as quality hardware is used they shouldn't move!! Just look at all of the Honda V-Tec stuff.....That's all solid flat tappet. How many miles do they run?
Basically check the valves adjustment after the break-in process (which is more than typical since it's recommended that the inner springs be removed for the initial break-in anyway), again at the first oil change (500 miles) and again after the first 3000 miles. From there it's pretty much done unless there's excessive wear or something comes loose. Just check them periodically.
You'll spend more time and effort tightening the header flange bolts and replacing burnt gaskets than checking the valves!!

and the performance difference is substantial!! :devil: