I have played this game for so many years that soldiers are just expendable to me, specially rookies. Exploring a map can be really hazardous to troops so I still tend to use HWPs to do the initial searching. Soldiers go next and then the Officers. I can't fit a HWP inside most UFO's, so breaching them is a rookies' job. I usually send them in with a live explosive, in case they get shot to death, otherwise, they throw the device and get the hell back outside.
I never sack personnel, and if someone is specially weak against PSI attacks, they join a team to be the walking ammo box and PSI Beacon. Since aliens tend to PSI rape weak minded humans more often, they keep the rest of the team more safer from PSI attacks.
If ppl die, they die. I stopped with the "save at every step" thing when I was in College but I only load a game when the entire team is lost... Too lazy to wait for a new Skyranger to arrive.