The Forever War

This book is number 25 on the Hugo List.  It starts in the present, 1996 to be exact and finishes in the year 3143 a span of 1139 years.  The main characters live through this entire period due to the tricks of time travel and using collapsed stars to move around the Multiverse.  I understand completely. There are parallels in the book with the experiences of Vietnam Vets returning home but they didn't have computerized suits of armour like these guys.