- Character's horses have names. Some characters get attached to horses, some don't, but all of them give a unique name to their beasts.
- Fast Traveling: ONLY when on horseback or I'm low on time. Half the fun of quests is all the stuff you run into just getting there.
- No HUD. I play with headphones and can easily hear the heartbeat sound when you're low on health, so I know when to run/cast a healing spell/down a potion.
- Eating, sleeping, and drinking are essential. I haven't found a mod that I like to emulate the need, but I do try to feed my chars when it makes sense.

Those are about the only ones I stick to universally. Depending on the character I also avoid picking up certain items like armor, weapons, or magic memorabelia.

My current character is a permanent level one. No leveling up, cannot assign health/stamina/magicka (each stays at 100). This also means no skill points assigned, no perks used.

As far as armor and weapons are concerned, you live off the land (loot drops, dungeon drops, or purchasing from traders.)

This also eliminates smithing and enchanting - so no need for soul gems. (you can do a little smithing, but it's not really worth it to get a 2H greatsword increased from level 21 to level 23, because if you level up, your enemies get stronger.)

The only drawback so far is that you cannot get the "Boethiah's Calling," quest because you have to be level 24 for that. Have not had any problems with other quests.

Additional limitations can be imposed if desired - for me, the above was enough. Especially, not getting the perks makes the game harder. For examply, my sneak is at 84, but actually without the perks it's a lot lower, and you can't sneak around as if nobody can see you.