Nah, never for that kind of reason.
Technical issues or mod conflicts, however....
*starts 20th character*
I've done it for sillier things such as being bothered with my character's chin length, back when Galathil's services weren't available to PS3 users.
I deleted my Altmer vampire because I'd created him to be morally good, and for the longest time I didn't realize what a terrible contradiction it was.
Also, my Nord werewolf because he would be the third Nord among my characters and that would've been too much.
There are others I started over, don't really remember why.
Won't ever be able to smith stalhrim armor (Dragonborn DLC) because the important character from the questline DIED by a lurker near one of stones on Solstheim. I have no idea why Bethesda didn't make it so that he gets down on one knee when "dead", but whatever that is typical Bethesda logic. This made me want to start a new character til i said screw it and realized i can still purchase stalhrim equipment.
No, there are sometimes ways to work around quest glitches. Even if quest tells you to go to X-cave and kill so and so and you've already cleared out the cave then going back every thirty days till you've killed a requisite number of enemies can do the trick.
It becomes more problematic however if you have the DLC's DG or DB installed and a quest giver is killed by random town attacks. At that point you have to make the decision to restart from a previous save or continue on without the quest. It is good for just this reason to have a working knowledge of the UESP Wiki although it is a heavy spoiler. Better though than having a quest short-circuited because someone essential has been slain.
No, if a quest giver is already dead the they're dead. DB and DG however load their own NPC's to add quest givers to the storyline so no need to worry about that. Problem is that DLC random attacks CAN and will kill vanilla quest givers. Also on Solstheim Lurkers can kill Skaal vital to "A New source of Stahlrim" questline which leads to being able to smith your own Stahlrim weapons and armor. Without that quest you can't smith the materialthough you CAN improve existing equipment.
For your last question any town or village you walk into after installing DG can result in NPC deaths due to vampire attacks.
That issue can easily be settled during the
Also a good idea for DG is after you install the DLC to hit and finish the DLC MQ quickly while staying out of towns and cities. This will keep your vital NPC's safe.
Aside from DG there are none I can think of.
I had to restart my very first game. I didnt realize how much more powerful certain enemies would become, and placed my skill points in things planned for long term use, without focusing on any single combat ability. After a few levels i could not really even fight Bears, let alone Dragons. I realized that trying to fix it (by gaining more levels focused exclusively on combat) would take much longer than just restarting the game.
I only made that mistake that first time though.
That actually happened on my very first Meleineth Elbenin character for 360, the 2nd was light years beyond him at the same level because I allocated my perks more wisely.
I had to restart my character due to my own Idiocy once.....
I was opening up my machine to throw in some new DDR3 RAM, and to get to my RAM slot I had to take out me HDD..
so take out the HDD, and put it on the edge of my work space, this was roughly 1AM.. I hear a large bang downstairs in my study, and immediately think I was being robbed. so I end up flinging my HDD across the room while grabbing something to defend myself.. I go downstairs and turns out the cat knocked over some stuff on the book shelf....
that HDD never worked again... so I wen't out and bought a new one...
only other time I had to restart a character was simply because I am bored of my current one...
Anything other than your major skill base dependent on the type of character you play. As he was/is a stealth/archer/light armor/melee character I invested heavily in light armor, one-hand, block and perked them heavily then moved to archery and stealth. Once you have a working idea of your character type you can break him down into major/minor skills. At level 30 or so you can start branching out into other things with this build like smithing and enchanting or alchemy.
My Nord warrior on PC is heavy armor, one-hand (For now), shield and bow. These are the ones I am perking heavily. I have already invested one perk in smithing but all my melee skills are being maxed from the bottom up. Since he is going to use no spells I am not going to perk any spell classifications, lockpicking or pickpocketing though I am going to invest some perks in two hand and perhaps stealth later as he goes to a two-hand weapon. Stealth if iffy as is alchemy.
No. I do not compute with mistakes, except for killing an NPC that automatically makes it impossible to complete a quest that grants you the ability to craft Stalhrim.
Unless you are an evil character and want to depopulate Solstheim look at my spoilers for DB and the Skaal. same NPC.