You don't need much at all as long as you have a fully paid flat, kids and meet your
CPF min sum.
If you meet the min sum at 55, and if both husband n wife working now, they will each get $1200 from
CPF life. So you get $2400 pm.
You can rent out two spare room for $1000 per room. You get $2000 pm.
Your 2 kids give you both $1000 in total pm.
So, combined passive income is $5400 pm. This is a lot for a retired couple.
All this is possible if:
1. You both meet
CPF life min sum.
2. We have many FTs to rent our spare rooms.
3. You have 2 good kids to give you allowance.
This is the secret for happy retirement.