You have to decide if you want to live on the east or west side (if you go into the MM2H retirement program) as the criteria is different.
Ok.....im in my 22nd year and personally Ive had enough and want to go. But as Ive said before in this forum, Malaysia is definitely ideal for retirement if that is really all you will be doing. Prices, though climbing steadily, usually remain lower than any western country. Climate, people, food cheaper, nice overall environment, beaches, islands, palm trees, lower prices for medical and dental. Its good for retirement but quite terrible if you want to do anything else like have a business or need to frequently deal with govt.
Financially, if you are alone you can survive OK on US1000 a month. For a couple, US1500. But inflation is always present so maybe in four years you have to add 30-40% to those prices AND be able to handle such increases in the future. If you want a more luxurious life, double or triple my estimates from today. So, on US3000 a month, I could live really well. In fact, personally, I would be gagging on so much money, I wouldnt know what to do with all that. Of course, US3000 is a drop in the bucket for others, they need US20,000 a month.
My advice, as usual, is to come on several 3-month trips and check out everything and spend how YOU want to spend, then decide.
Also, dont just listen to people who say take the East side because of an easier retirement program. This is silly. East and West is different flavors, people, situations and money alone doesnt account for how you would enjoy it or fit in. Personally, I hate the East side and would never live there. Hate the people, the scene, the food, etc. So experiment with both and see and absolutely please dont simply come. Take your time on experimental trips because you might find you dont like either side and will ditch Malaysia completely. If you signed up for programs without the experiments, you might be sorely unhappy. Of course you might be very happy too, im just saying.
So, financially, its hard to predict but as of today looking at four years from now, if you have US2000 a month and can afford 10-15% annual increases, I think you'll be fine for average living as a Malaysian. You might come to my house and think, Hey, excellent, this is great! Or, OMG you live like this?? And run down the street screaming. I dont live like I did in US and wouldnt live like I do if I left here. Living in a place is partly about where you have been but mostly about where you are. Ive made a lot of changes to live like I do, changes that others may or may not ever be willing to make. My goal was to live as a local and im not unhappy. Some expats want and expect to drag their whole past life with them which to me makes things harder and much more expensive. They want their clothes, furniture, pets, cars, foods, whole way of life. In my experience thats not a very good idea but they figure into your question about how to prepare financially. Everything depends on which way you want to live.
You didnt say if you are rich or poor and that makes a difference. I assume most people in retirement are on a budget so I gear my posts that way. If you are rich, dont bother reading. Otherwise, to keep things financially sane, let go of everything, come with the shirt on your back and in small increments build up your life to your minimum comfort level starting with a US1200-1500 monthly budget, notwithstanding the requirements of a specific govt retirement program if you go that way.