I give raises when someone proves they are worth it. If all they do is push the green button and show no initiative of expanding their skills or responsibility then their raises are gonna be CoL increases and that's about it. If someone is busting their ass taking on all the projects I give them and asking for more, and always asking me to teach them stuff, then I am inclined to give them a raise. There also comes a point when I can't afford to pay someone more, since I am not google and I don't have infinite money.

If someone out of the blue says they want more money I will ask them to tell me why they need it. Their answer does weigh in, but even if they answer "I dunno I just want more money" I will still seriously consider it and see what I can do, but I tend to only give raises semiannually because that is how often I reorganize the budget, and often won't have much room for raises between those.