I was living in DC area but was traveling to Bay Area every week (mon to fri) for work.
I always booked fare in reverse with Friday evening departure (from sfo) and Monday morning ( from DCA) return. A Saturday night “stay” apparently made it a leisure fare which was way cheaper than Monday to Friday fare which was way more expensive. (Like 4x more). [ this was United Airlines btw].
My understanding is that this does not work anymore (at least for US domestic). Airfare are all priced for one way (return fare is just the sum of two legs).
However, difference between what business travelers pay and what leisure travelers pay is huge (see hertz rental prices or Marriott hotel prices for saturday vs Monday).
Just looked up economy London-Singapore return, Sunday-Sunday in economy on BA Aug 7 to Aug 13
and there's space in the 'M' bucket with fare MHNC80S7 which is £510 each eay (plus fees and taxes)
TRAVEL FROM LAST INTERNATIONAL STOPOVER MUST COMMENCE NO
EARLIER THAN THE FIRST SUN AFTER DEPARTURE OF THE FIRST
INTERNATIONAL SECTOR.
Come back a day earlier though, Sunday-Saturday, and you can't use that fare. The cheapest they offer is in the "Y" bucket, YNNC80S1, at £1131.50 each way
That means the extra day in Singapore saves you £1200. (the taxes and fees are the same regardless)
If you travel a lot - especially flexibly - then it is sometimes worth a subscription to expertflyer, which if far faster at seeing rules and availability than traipsing through ITA Matrix.
I used to have the same itinerary more recently, and managed to lower the costs on United by 20-40% by booking overlapping itineraries >7 days long, where I'd:
I was living in DC area but was traveling to Bay Area every week (mon to fri) for work.
I always booked fare in reverse with Friday evening departure (from sfo) and Monday morning ( from DCA) return. A Saturday night “stay” apparently made it a leisure fare which was way cheaper than Monday to Friday fare which was way more expensive. (Like 4x more). [ this was United Airlines btw].
My understanding is that this does not work anymore (at least for US domestic). Airfare are all priced for one way (return fare is just the sum of two legs).
However, difference between what business travelers pay and what leisure travelers pay is huge (see hertz rental prices or Marriott hotel prices for saturday vs Monday).