I always wash dark clothes in cold water to prevent fading of color. For whites or light color items I usually use hot, but if you pretreat stains, you can still use cold water. To Pretreat I use the same detergent I use to wash the clothes. For instance, I like to use Tide because its a HE detergent that works in my front loader. I pour out the necessary amount or 1 load, dab the stain with the measured amount, let it sit for 20 minutes hen run a load.
I also have a soak cycle, that seems to soften up stubborn stains. But I also have dogs and sometimes their bedding is foul, I run that on water as hot as possible.