There is no golden ratio, only total capacity one can handle.

Regardless how much we earn
- egg cost the same
- roti canai cost the same
- petrol cost the same
- utility cost the same
once can go for premium service, but the baseline is the same for everyone to basically survive.

Ask someone with 1500 per month to buy 18k used car base on 12 months guideline will kill the person
Someone that make 100k per month can spend 50k installment on multiple cars, who are we to judge him/her? After deduct tax and installment, still can make a decent life.

You know what you can/can't afford.

Sorry bud, not everyone la just some and when come to figures kantoi lo. Nevertheless popcorn time is just over haha.