For a starter. The 900 limit is a European legal limit. It is intended to work more for long haul crews than shorthaul.

How many people could do a BOS 19 hrs off then a BOS night flight to LHR , followed by a Chicago ... 24 hrs off then then ORD night flight to LHR, then 3 days off, then a LAX. 48 hrs there. Then LAX night flight to LHR 3 days off. Then a night flight LHR to HKG 2 full days there then another night flight HKG LHR . 4 days off. Then a BOM horrendous flight. 20 hrs there . Return flight. 2 days off. ...... Then do it again and again and again for 35 yrs?

That is 26 days work for a full time crew member. That was my last ft roster. May I add that isn't the worst roster either.

The 900 hrs limit is there for a reason. It doesn't become law yet, but I can't wait for it personally.