Rune Factory questions (Nintendo DS)

[Merkuri]

So, I'm playing Rune Factory for the Nintendo DS and am loving it to death. I'm trying to do and figure out everything myself so I don't want any big spoilers, but in a lot of cases I find hard to find information on things and a lot of it seems to be counterintuitive so it's hard to just guess.

So I'm hoping some EN Worlders who have played the game can answer some questions for me. A lot of these I think I know the answers to, but want confirmation.

For reference, I'm in the middle of my first winter, have cleared out Carmite and Toros, and have gone into the next cave (the name of which I forgot) once. If possible, don't give me any spoilers.

1. Does food ever spoil? It doesn't look like it, but I noticed the "expiry" entry on each food item and my first thought was it was the number of days the food took to spoil. Is that really the amount of time you're "full" after eating that piece of food?
   
2. Do higher level crafting components/ingredients (like gems, metals, and crops) give any sort of bonuses to crafting/cooking with them? I haven't seen any benefits so far to using higher level items in crafting. Is the only benefit to higher level gems, metals, and crops their selling price?
   
3. Is there any benefit to "charging" the fishing pole? Doesn't look like it, but my fishing level isn't very high and I wouldn't be surprised if the effect became more apparent as my level went up. If there is a benefit to charging it just a simple "yes" answer will do. I don't need to know what the benefit is.

I think that's all I have for now. I might come back with more questions later.