HP ZR2740w seems dim

I've had an HP ZR2740 IPS LED monitor about 16 months now and I'm noticing it's not as bright as my newer twin Dell Ultrasharp 2412s which are about 8 months old.

Full Disclosure I use all my screens MAX brightness and NEVER turn them off. I mean literally I think they've been set and running at max brightness and contrast since they left the boxes. (only now finding out that may speed up aging of the backlights)

That said I work in a very bright environment and can not tolerate lowering the brightness in fact most monitors below 300nits are simply unacceptable so essentially I'm asking 2 questions...

1. Is 12 000 hours or thereabouts enough wear and tear that might require a backlight replacement.

2. Is such a procedure offered anywhere or am I faced with having to replace every 18 months assuming I can not work with lower brightness and contrast settings?

Thanks in advance,

MichaelC
Amphetaman@mac.com