I was curious about the island hopping that occurred in the Pacific Theater of WWII. Mainly, was it just chance which island you were deployed to? I ask this because my grandpa fought on Iwo Jima, but did not fight again. Was this just luck? I can not imagine there was enough man power to let every soldier who fought in one large battle to not fight again. Thanks in advance.
They US strategy and MO for the series of amphibious landings in the last 2 years of the war was relatively straight forward. It came down to having trying to balance amount of time units spent fighting, and not letting them sit idle for too long(but long enough for them to replenish ranks) and have them contribute to the ever moving drive across the Pacific from the Solomons all the way to Okinawa. It basically worked out that for most Marines their unit would be involved in every other landing.
The two major formations for this by the Spring of 1945 were the III Amphibious Corps consisting of the 1st, 2nd, and 6th Marine Divisions. And the V Amphibious Corps with the 3rd, 4th, and 5th MARDIV's.
The VAC as earmarked and landed on Iwo. While the IIIAC was at Okinawa, however both would have been involved in operations Olympic and Coronet as part of the planned invasion of the Home Islands.
This is of course separate from the HUGE contribution by the US Army for the landings, for instance of the 180k troops landed on Okinawa 100k were Army soldiers.