Taken from the Island Hoppers map, played as the Empire of Kand:

"When I got the first depot as the Empire, I moved the interceptors immediately to engage fighters on his island. They fought, and since they were superior in strength they didn't get wasted immediately. They had to do something while I was waiting for his transport to come in range, and it had to come in range of the interceptors if he was to take the middle depot. When that happened on the next turn, my interceptors had racked up enough experience that the two of them together took out his transport on one turn, so he didn't get to land his infantry and take the middle depot. That was the decisive moment of the game, actually. After that, it was just a matter of taking out his troopship with fighters."

Since they usually deal more damage, it's encouraged to let them attack stronger units first, while your weaker units finish those weakened enemy units off, yet at the same time also protect your experienced units more.

Repairing units makes them lose some experience.