does anyone just casually delete your high level characters and start again even if you have quite a bit to do?

No. I always backup my characters before I start a new character.

No. I was forced to delete my first and only character (so far, starting a new one soon) due to game breaking lockups, I still regret the decision to this day.

i cant do that i cant have more than 1 character at once

...And why in the name of all that is deep fried would I do that?
Even worse, why casually?

i just get bored of what im doing so i delete it and start with a different build

Ah ha. Well, to answer your inquiry...No. I don't do that.

i never have more than 1 character, i dont see the point

would you delete it if u get bored?

I casually delete every character I grow tired of.

I still have the save-files for old characters, but I wouldn't really care if I accidentaly deleted them one day.

No I'd stop playing for a while. I never get bored of Skyrim though, could spend hours simply chopping wood. Only reason I stopped in the past was due to lockups, which I pray won't happen again in my new save.

No if that's the case, I shelf the game and turn my attention to something else.

I'm usually bored with or have done all I want to with a character when I start a new one so I delete them
I used to keep them on the theory that I might use them when an expansion or quest mod came along but I found I never did, I always used a new character, so I've stopped keeping old characters

I have more than one character so no I don't delete it, however I mark the last save of the character with their name everytime I want to switch.

I abandon characters casually, but I don't delete them.

I definitely think it is a good idea to have multiple characters

I love the character creation and if you start afresh, you can have a totally different gaming experience. I think It's kinda silly that with one character you can be Listener of the Dark Brotherhood, Guildmaster for the Thieves' Guild, Archmage of the College of Winterhold and Harbinger of the Companions. Then of course you've got the Dragon Threat and saving the world. Then the Civil War. Why do everything with one character? I enjoy making multiple characters for the role-playing element. Thieves' Guild and Dark Brotherhood complement each other well, as both require stealth and after all you do work with Delvin whilst you're in the Dark Brotherhood. Main Quest and Civil War go together well (but that's not to say you can't do that with the other factions thrown in as the main quests are central...) the College and Companions stand out separately however I think it's good to go into the companions and then the Dark Brotherhood - a werewolf assassin is pretty awesome and Arnbjorn is much more welcoming!

I do have a character that did it all barring the College of Winterhold and Civil War. I think everything else went together well for her character and I've had a great experience with her. I just think it's nice to vary your characters and do things differently to your previous play-through. For example, you could do "In My Time Of Need" differently. "Delayed Burial". "The Cure for Madness". Make a good or an evil character - perhaps with one character you'll join the Dark Brotherhood but with another, you'll destroy it.

There are so many simple little choices in this game, and some major. Try experimenting with different playing styles and I promise you Skyrim will always be alive.

I'm kind of like this, I always feel like the character I have made is actually me, hence why I'm still on my first character and dont intend to ever delete him / me!
If I eventually run out of things to do (200 hours and counting so far) I'll do like one of the previous posters and move on to the next challenge (dawnguard, dishonoured...)

I casually overwrite the saves

No, sometimes I delete the lower level character that I don't use anymore. The only high level one I deleted was by accident

No, I might not play on some of them, but I'm not going to delete them.

If I start a new character I will generally eliminate a barely used character. I deleted my altmer mage because I never used him and replaced it with a poison assassin.

My high level ones always get bugged. My last toon got stuck in stealth mode and I couldn't get it out. Even had the abilities like the silent roll without a perk spent in stealth so I had to delete it and start over.

Very frustrating.

This. Even though there's almost no chance of ever going back to a character (esp once I start making them with specific mod sets), I still make a copy of the last save before clearing out the save folder and starting a new one.

Not my main who is about level 65 - 70. There are a couple aperk points I wish I could move and I didn't realise you had to kill the dark brotherhood leader in the hut as I had no intention of joining them and always planned to wipe them out. No it won't let me.

I've covered too much ground to delete that one. Some of my other characters that were about level 20 I deleted and started again. My Redguard I did as a Hamerfell military with full Dwarven heavy armor but as I looked at the Redguard stats I realised they were more suited to no armor with alteration for defence instead. I'm glad I did as it works quite well and makes them unique to other races.