I have recommended this before, but I will do so again here. Can I recommend the MyFlights app. It allows you to add amadeus/sabre booking (so ok for BA ticketed bookings) and constantly monitors them. If anything gets changed including flight times, seat numbers, flight numbers etc. you get a notification on your phone and an email which highlights the change.

You can also add and view booking on their website as well.

http://www.myflightsapp.com/

It is a good way of knowing if your booking has changed instead of waiting for am email from BA or noticing it on your BAEC page.

Unfortunately whilst AA are on sabre, and sabre is supported, AA (and also AF) do not allow 3rd party tools to access their flight information so can't be added to myflights. Therefore, if you have an AA booking with no BA flights soo only have an AA sabre PNR it can't be added. If your AA booking has a BA flight and therefore a BA PNR as well, you can at least add the BA PNR.

Of course if you have a BA booking and BA PNR, and the booking includes AA flights, you can add the BA PNR and the AA flights will also be monitored and you will get notifications when any changes are fed across from sabre to the BA PNR on amadeus.