If your bicycle is set up correctly, and you've got a good saddle, and you've developed good core muscles so you are sitting on the saddle properly ... you'll greatly reduce the chances of saddle sores.
I rarely use any creams at all on my rides. I did experiment with them one season, but found them to be sticky, messy, uncomfortable, and not worth it.
However, you do have to take care of your skin in really hot weather (because you sweat lots), and in rainy weather (because your shorts will be wet).
If you are sweating lots, it helps to stop at a gas station washroom, or something similar, along the way and wash yourself with water, then dry yourself well with paper towel. If you do not have the luxury of clean water and something to dry yourself with, baby wipes can help. Washing away the salt from the sweat helps reduce the chances of irritation.
If you know you'll be riding in rainy weather, a cream of some kind can help protect the skin. Wet skin is fragile skin.
After the ride, have a nice hot shower and wash well with soap and water. If you have no rashes or anything, you're good to go. If you do have a rash, apply some zinc oxide cream to the rash. You might want to wait till just before bed, and whether you are a male or female, I would recommend wearing boxer shorts to bed because zinc oxide cream is messy. In the morning you should be good to go.
122240 km ... and only one saddle sore.
