Is there an underlying issue which you're not sharing? Do you have concerns about the injectors?
I consider the whole of the injection system to be non-serviceable. No reason to doubt that it should last the life of the engine without trouble.
I'm a big believer in "if it ain't broke, don't fix it". I do believe that you should service the engine annually in accordance with the schedule published by Volvo.
My MD2030 has 800 hours on the clock (or did the last time the sun warmed the gauge sufficiently for it to share its secret).