I have very little experience in asking for pay rises. On the whole I have either been with employers that offered regular raises to their staff, or have left companies that were unable to provide raises due to financial difficulties. My current employer is in neither situation but they have not given me a raise in three years.
It's hard to judge, but market rates suggest I am marginally underpaid. Recently I was approached by an old colleague, who offered me what was, on paper, a 10% raise. This would have been nullified by the fact his company was new and offered no perks or benefits whatsoever, so I turned it down. But other opportunities I've seen suggest that I could earn more.
Right now, I feel like I'm in an extremely powerful negotiating position. I have a "bus factor" of one: there is business critical knowledge in my posession which no-one else has. My company is about to undergo a merger due to an acquisition and my counterpart in the other company is about to leave and will not be replaced. So, amazingly, that unique knowledge will then be business critical to an even larger company. Essentially I wrote an internal software product which is used throughought the company, is largely undocumented, and written on a technology stack no-one else has experience with.
In defence of my employer, I do have a three month notice period. So if I were to leave, there would be a made scramble to find someone to replace me ASAP so I could do a handover. It's also worth mentioning that the "direct value" I bring to the business in terms of income is hard to quantify, and I have no big wins I can leverage to demonstrate my value.
The trouble is that although I have a strong hand to play, I have no idea how to play it. I don't know how aggressive I can or should be in demanding a raise or threatening to leave. There's plenty of other work in my area if I did walk away, but I don't really want to: I like it here, the work is interesting and not unduly onerous.
I'm going to talk to my line manager about this soon, and I don't know how hard to push it, or how to phrase my requests without seeming arrogant. I don't want to be seen as being a flight risk. I don't want a promotion - just a cost of living-type increase. There is a lot of other stuff going on right now with this merger but I don't want to be made to wait. I don't even know whether to mention that I've been approached and offered a higher salary (my current employer doesn't need to know it was level-pegging after beneifts, obviously).
How tough do I play this?