Instead of the old 1 year gross salary equals to the car you can afford, I think the rule of thumb of 2 years saving excluding bonus and other income equals to the car you can afford to be most reasonable.

1 year gross salary equals to the car you can afford doesn't make much sense because some people with 20k salary after deducting all the commitment might have a monthly saving of 2k but a guy with zero commitment who earns 10k could save 5k every month, which makes the 10k salary guy are more able to afford more expensive car than the 20k salary guy.

The 2 year saving rule make sense because anything less would make it unreasonable for the average man to buy a car unlike super ultra wealthy people who could just spend 1 month of their saving to buy a Ferrari easily while anything more is a bad financial decision cause for an asset that only last 10 years, the more you stretch your saving on an item that depreciate over time, the more it feels like you are slaving away your life just for that temporary status boost or self satisfaction.

That is a dangerous rule.

If you have 1mil in savings, then buying a 500k car makes little sense. You are throwing away half your savings every time using that rule.