This is based on my experiences in the UK, trying to recruit quality people into Senior positions. My conclusion, there is a very big difference between how people view themselves and how I view the role of Senior Developer. The average salary request for a Senior Dev in the UK (outside of London) is about £50K+ ($65K+), which for many companies is a lot of money to pay out in addition to the recruiters fees, which can be anything up to about 25% of that yearly salary and all of this before you even know whether the person is any good.
I am an employer and I get nervous when I interview someone. They are usually polite and of course they can do the job that you need them to do but the simple truth is that the recruiter and the potential recruit have a virtually zero-risk opportunity to talk themselves up to convince me they can do the job. If I take the risk on them and they are not very good, I either have to let them go at 3 months, losing several thousand in recruiters fees and potentially wasting a lot of time on a person who takes more than they are bringing to the company.
If you are that person who is applying for a role at my company, what am I going to ask you?
Firstly and hopefully this shouldn't be a shock, I am going to ask you about your experience in the areas of the job description. Example: This position requires a strong interest or experience in web application security. "Tell me about your experience in web application security", "I haven't done much". "Then why are you here wasting my time just on the hope that somehow you will convince me that I should still take you on?"
We even had a guy apply for a Development Manager position and all of my questions about, "What will you need to do as a Manager that you don't currently do as a Developer?" basically caused responses along the lines of "erm...", "hmmm.." as if the person hadn't even asked himself what a Development Manager actually does.
Secondly, I will ask what it is that makes you Senior (even if you are not a Senior, I would still ask you what separates you from the crowd) and I am fed up with the number of times that the answer is basically, "It means I have more experience", "What experience do you have that a Junior doesn't?". "Ermm...."
What do you know about Dependency Injection? IoC Containers? Test-Driven-Development? Deployment? The cloud? Node js? Angular?. These are all things that I would expect a Senior Developer to understand. Not to be super-experienced: we don't all get to do these at work - but anyone with any decent interest in web design meets these subjects all across the web. Even if you don't know exactly what it is, do you not even know the basics of why an IoC container might be useful? If not, why not?
Thirdly, I will ask why you are special. So you know some stuff about .Net and you have been programming for 15 years? Top tip: I don't care about anything before the last 5 years because we don't use Web Forms, VBA or FoxPro here! We are a startup and it takes commitment, interest and passion. Don't have a blog? Why not? Your own web site? Involved in any clubs outside of work? Developer hangout events? Member of an Institution?
The simple reality is that for most of the people we have interviewed, the sum total of their CV is: I have been writing code for average companies for X years and there is nothing that demonstrates that I am anything other than a sheep who will do what I'm told but I never think of the bigger picture and my job is largely just to pay the bills.
Even though the market for Developers in the UK is massive and the supply is terrible, I will not take any person on who is asking for £50K just because they have 15 years in the business. If you want that Senior Developer job, you should love coding. You should love it so much that you can easily demonstrate how much you love it. How you owned stuff in your previous job, you were the go-to person, you built stuff, fixed stuff, upgraded it, especially when you weren't asked to do it!