I learned early. First job out of school- at a start-up, a few years old. Was offered pay too low to live on in Toronto. I told them that- they sweetened it by 4%. I accepted. 3 days later I turned down 13% more money from somebody else- a major firm which was just a little too slow off the mark in making me an offer- I'm a man of my word and a deal's a deal. I went off for a month in Europe, came back, put first and last month's rent down on an apartment and still had $32 to my name...went in a week ahead of my start date to meet my boss. He said, "Hi- nice to meet you! Your pay's been cut by 5%". When I complained, he said he'd taken a 10% paycut so I could take 5. I started work making 18% less than I could have been making if I'd been less than a man of my word, i.e. like my new boss was. Welcome to the profession of engineering...
I was very fortunate that I got life lessons early, and learned from them. Life lessons hurt, and cost, much more later in life...