you could but only at the recommended interval IF the plugs are worn. I was shocked to see that at 160, 000kms that my factory twin iridium plugs had NO discernible wear or increases in electrode gap clearances. The factory twin iridium plugs do seem to last forever. I'm at 215, 000kms now and my plugs that I installed at 160, 000kms look like I just installed them still. I keep the old plugs to show others how good they were. Heck I'm sure I could reuse them for another 50, 000kms and STILL have no wear on them :)
But each to their own and there is no harm in being proactive - The twin iridium plugs here in Canada are $25 a plug so replacing them early when not needed can be costly.