It's easy to quantify - look for another job - if you're getting offers for a certain salary - that's your minimum value. Now ask for more. When the offers st

It's easy to quantify - look for another job - if you're getting offers for a certain salary - that's your minimum value. Now ask for more. When the offers stop, you've found your value. Likewise - you are more valuable to your current company as you have domain knowledge whereas a new hire will require training, keep that in mind.