You are doing very well indeed. When your children starts to work and get married, you can downgrade to a one bedroom condo unit. After selling your current condo to the small unit and paying in full, you should have cash in hand of at least $1m. For example, if you sell your current condo at $1.7m and then you buy the smaller condo at $700k, you have $1m in hand.

You then invest the $1m cash in good quality blue chips that give you 6% pa dividend yield. So you get $60k pa in dividends. If each of your children gives you $1k pm, you will get $2k pm or $24k pa. When you reach 65, you and wife will get $3k pm in total (assuming the min sum goes higher and hence payout is higher) or $36k pa. So you get in total $120k pa of passive income. So, you are retirement ready. Congratulations.