A percentage for saving is only part of the story. Its what you do with it that matters. When you retire, you don't want to have your eggs in one basket, ie an investment tied to shares. Not that the country will slide into the sea, but another big recession will hit much harder than the 2008 dip
The obvious investment is property and the easiest to manage in terms of less hassle per buck are flats, managed by a wide-awake body corporate run by someone with lots of common sense, not because he/she knows somebody or owns several units. Here, as in any other investment, you have to do your homework. Flats in a good area that sold for R300k about 15 years ago are now going for R1,5m. Its essential to get a garage with the flat, it makes it more attractive to let and sell.