Crome what I've noticed the characters will give you "kind of the same quest" but they only give you like 5 or 6 of them. After 5 or 6 they stop giving you quests and it's time to pack up and move on onto another town.

There is no rush to complete the quests. They are useful in that they will help you to level up faster, making the game easier when you play the main quest. Honestly, I would focus more on the story missions because you might end up being overlevelled and finding the game to be too easy. I'm level 30 now and on the beginning of chapter 6, and I spent a lot of time doing side quests before I realized this. Don't worry, the subquests aren't going anywhere and if you are a hardcore completionist, you'll be pleased to know that there is almost nothing missable in the game, and nothing missable as far as getting a platinum trophy/perfect achievement score. It's actually quite nice, unlike other FF games where a lot of missable quests and items would force you to follow a strat guide carefully. Just enjoy the game. The sub quests are not endless, and they will be there even after you finish the game. All I recommend is that you look up where to find magical flasks and Prompto's machinery because I think at least one or two are missable. Everything else can be 100%'ed from any point in the game, even after you complete the main storyline. Probably the most rewarding side quests are the monster hunts. And you'll want to keep an eye on those because they will culminate in the ultimate monster hunt against [spoiler][b]adamantoise[/b][/spoiler], who is the game's hardest enemy and takes about an hour to beat if you are at level 60 or so. And by the way, holy shit the game gets crazy by chapter 5. :-) Keep playing the story!

I don't believe they are never ending, but there are quite a few of them, I would suggest doing as many as you feel like then just moving on, I'm a few chapters ahead of you and the quests won't be canceled out or anything if you move on to the next chapter. What I did was just finish out all the ones I had then didn't pick anymore up until I was ready, that way my quest log wasn't all clogged up by shit.

I can guarantee they are not reoccuring. Im lv 70 and finished all those little quests, they eventually end. There are some higher level quests though I havent done. Mostly because they are lv 99 quests... But those fetching dog tags, getting frogs, power plant, etc. are not reoccurring