Its a difficult balance with work - If you earn a certain amount then you will be expected to work outside of 'normal' hours as and when needed. I sometimes have to work very long hours and its not because i'm disorganised or messy, its because I'm good at my job and as a result it generates further work for me - almost a victim of my success!
However, my remuneration is commensurate to what I do and deliver and as a result I don't mind putting the effort and hours in. There are people at my place who take no pride in their work or just do the bare minimum to get by, and these are the ones always complaining about their salary and bonuses (or lack of). I'm lucky in that my place recognises effort and productivity and it is tangible and demonstrable (basically, the amount of money people generate per month). I'll generally monitor my work emails until 9pm most nights and reply if I can - they are usually to clients, not internal emails.