How much do you think a person can save by hacking miles consistently?

I didn't actively hack miles, and have mostly accumulated them on Citi PM. Having said that, I have close to 300K miles now due to maximizing stuff like 10mpd on Kaligo, 7mpd on expedia (book for your family and friends!), and the occasional spend on certain Citi PM promos, as well as overseas spend on my holidays.

At a 1.8 cpm, that's around $5400 worth. I estimate that I have clocked around $120K (probably?) on my Citi PM over the past 6 years, and only really because I put most of my wedding expenses on it during the CNY miles promotion earlier this year, if not the number would probably be far lower. That means that maximizing my promotions and bonuses, I nett almost 2.5mpd on my spend, and that's with the fact that Citi PM doesn't really have specialized categories per se. Yes, I really should work on maximizing the 4mpds.

So $5.4K/$120K is around a 4.5% rebate. Beat that, cash back!

Anyway. 300K miles is pretty much 40K miles plus a return suites class to Newark on SQ's A380, which itself retails for $19.8K if you're leaving a month from now. If I cashbacked, I would have probably gotten $1.8K-ish of cash back.

So there's a reference point for you. This does depend on how much I really did spend on my Citi PM all these years, $120K being a reasonable estimate, but I would have to dig 6 years of statements to get the number, which I'm not about to start doing.

1. Know your cards well

Always know what your card is capable of and its limitation. E.g. 1.2 miles per $1 spent. $1.20 spent = 1.2 miles, not $1.20 x 1.2 miles

2. Know your cards' limitation

For instance, maximum cap at 3,000 miles per month. Don't spend a single cent beyond this threshold.

3. Integrate cards together

With (1) and (2), use cards that complement with each other.

4. Know the rules and when to break them

Can't say much, but always good to spend time to internalise the T&C and use it to your advantage.

5. Bonus miles are (almost) always worth it

While it is at times stupid, e.g. pay annual fee, the miles in return are always too good to let go

6. Plan early

With Points (1) to (5), create a calendar and know what to do. Then decide which airline to go for. Personally, I am with KrisFlyer.

If you do it right, it shouldn't take too long to accumulate 6 digit miles. Have fun! (But don't overdo it!)