I disagree with the advice to search ruins, especially early in the game, with a level 1 hero, even against a level 1 ruin. At near 50%, the chance of your hero dying is just too high. The outcomes have a disproportionate effect on the game. I would only risk it if desperate, if I am already losing.
The possibilities are:
1) Hero loses. You get nothing in compensation-- no money, no units. And, you can't afford a replacement hero. This outcome is so devastating it could be the game decider.
2) You get a pile of money. That helps, but only a little, and certainly not enough to justify the risk. You won't be able to make effective use of that money early in the game.
3) You get an item.
a) The item is a battle item, which is nearly useless. The only time that is used is when the hero is personally battling. Only takes a couple of bad rolls for your hero to lose despite the fancy weapon.
b) The item helps all units with the hero. This is one of the best outcomes. But, can achieve the same result with a lot less risk by leveling up.
4) A few powerful units join you. This is real help. I presume this can happen, but I have yet to see that outcome.