Hi could someone give me some advice on when (which age range) MINDEF insurance by AVIVA will not be cost viable anymore?

Aviva Mindef insurance is cost effective as follows from my calculations

1) Death - Anytime you can buy and by age 66 there is a steep increase. So if you plan to have coverage after 65, do compare private insurance cost with this.

I would urge you to get private insurance for death first, then top up with group term because the opportunity cost to top up is cheaper for Aviva Mindef compared to private.

2) CI - most likely age 30, because private CI plans may be slightly more expensive at the start, but levelled. Aviva Mindef has a tiered system and cost more each group band till 65.

3) ECI - not worth to get it totally, can skip it (i cancelled mine).

The policies are not cost effective after age 65.

The Living Care Plus is not comprehensive as it covers only 10 early CI conditions while other private policies can cover up to 100+.

The Living Care is fine.

Just note that the rider premiums are not level and increase by age band, while a private policy will have level premiums and won't change as you age.