1) are you pretty good about cleaning/soaking regs well after your prior trips ?
2) do you store your regs in climate controlled (cool) conditions ?
3) are you religious about keeping the 1st-stage dust cap tightly closed whenever the reg is not being used ?
4) have you inspected the condition of the 1st-stage inlet filter for any signs of corrosion/discoloration (indicating exposure to seawater/compressor oils/rust flakes) ?
5) have you hooked the regs to a full tank, and made sure they are operating properly ? (breathe fine/no air leaks) Or better yet, have a chance to do a test pool dive with them soon? (one little trick is to attach your reg to a tank, pressurize the system, record the pressure per your SPG/computer, leave the unit for a while, come back and see if/how much the pressure has dropped, which will help spot 'leaks'.)
6) have to double checked all the hose connections/fittings to make sure nothing is/has worked itself loose?
7) how many dives do the regs have since last service, less than 100 ? (generally a properly cared for reg should easily go 100 dives between 'annuals')
8) do you have access to on-site rental regs if yours fails ?
...if you answer 'yes' to everything above, servicing probably is not needed. If you do service them, make sure to test them before your trip!