Daegu and Seoul - able to retire in? how much retirement income needed

I read on wikipedia the average gdp per person in Daegu is around $22,500, and Seoul its around $35,000.  I'd like to retire (or maybe spend some retirement years there) so I'm trying to anticipate how much income I would need for myself to live comfortably (and hopefully someday with a significant other).

1.  Is $40,000 a year enough to live comfortably in Daegu?  (I've done the numbers on living expenses and it seems like its more than enough, but maybe i'm missing something)

2. Is $50,000 a year enough to have a studio and go out every Friday and Saturday for fun?

3.  Would anyone advise for or against either one of these cities or recommend another city?  I picked Seoul as a target because its Seoul (large, metropolitan, yet very asian).  I picked Daegu cuz its the 3rd largest city, with a low GDP per capita therefore more bang for my buck, but still has over 2 million people so its not a small town but has big city amenities (i.e. i dont want to retire in a small village no matter how cheap it is, otherwise I would retire to Thailand or the Phillippines with a fraction of my income haha)

I know this is a broad question but, the GDP per person numbers i researched seemed extremely low.  How could the average person in Daegu make $22,500 I wonder.  

Just wonder if anyone has experience with budgeting and what kind of lifestyle they can live with their income range etc, they can let me know about.  (I lived in China and Japan for years so i can write a book about incomes, lifestyles, and spending habits haha there).  for example, about 10 years ago, a $30,000 a year income in China would have allowed you to live like a rich guy, but now, not so much.  So was wondering if anyone can help out a Korea noobie with some insightful info.  

I did some expenses research and assumed i studied korean and lived in their housing, with school, housing, food, phone, subways, and health care being around 20 grand a year.  If you spend 200 a week (maybe $100 on Friday, $100 on Saturday eating out/drinking) that adds another 10$ grand in expenses, making living expenses being 20 grand base, 30 grand is base + having fun.  So is it realistic?

Would having 50,000$ a year allow me to live comfortably in Seoul? would i be able to have a blast? penny pench/shoestring it? ( had a buddy who got 5,000$ a month from his parents while in Tokyo, and he went through it like water and had nothing left over.)  

Side Notes:  I have been to Seoul 2 times for about 3 weeks total.  

Re: Daegu and Seoul - able to retire in? how much retirement ...

It's enough, maybe your friend went to the expensive Korean places with 500 dollar bottles of liquor.

 

Studio in Seoul is about 800 a month, a studio in Daegu about 400 a month, and goes up from there.

Food isn't that expensive and is cheaper in total than going out back home, depending on how fancy you get.

You can retire here, but it's no Thailand and you won't be living like a king but you won't have money problems if that is your pension.