The ettiequte for how long depends on several factors. But fukk ettiequte. If you think you deserve more money, ask for it. A few things you could/should do.
SHOW, not tell, how your routines/responsibilities have increased since you were hired. Use numbers if you are able to. Companies only care about the bottom line, so you have to show them where and how you bring value. The best thing to do is to show how you’ve improved efficiency or saved/made money. Have you improved any processes? If so detail that. Are you willing to take on more responsibility? If so express that.
Do some research and find out what someone with your same amount of experience, education, skills, in your region, in the same role makes. This will determine your market value. See if it’s in line with what you make. If it’s lower, bring it up. One tactic is to request to be brought to at least market value. If you make more than market value, no need to bring it up. You also need to find out what your role makes in general in your company. You may be under market value for your city or region, but paid fairly compared to others in your company.