Thinking about quitting your job? Go tell your boss
ronsho.com
ronsho.com
But that's a rare situation. Basically, it's people who were hired as junior engineers and have leveled up. Years 2-5 of your career are when your position can become mismatched with the broader market.
If you're just testing the market, and you might find that your current job is your best available option, don't tell your boss. Similarly, if you're fleeing a bad situation but you need the paychecks for a little while, don't tell your boss.
If you are ready to leave, you're giving up control of when and how once you tell your boss.
It's exceptionally naive to think that everyone will structure the nature and timing for your benefit instead of theirs and/or the company. You may be asked to resign on the spot or give notice. In some secure environments you may be walked out by security on the spot.
Additionally, if your plans fall through or you have a change of heart, you will be regarded as disloyal, which may follow you and impede future promotions or assignments.
Finally, if you have a vindictive boss with contacts in the industry or destination company, they can quash existing or pending job offers to keep you or punish you. Cf. Jobs/Apple/Google
I'm not saying these are great places to work, but they exist, and I bet they're not the minority.
In engineering this may apply, as it's a buyers market. Most bosses (in engineering) understand that they need to convince you to work for them.
It's possible that "Ronsho" could use a little more exposure or real world experience before making blanket statements.
Something had to have pushed you to do all that work to find a new position; are a few thousand more a year going to fix it?
Never mind you'll forever be marked as the "one who will leave".
I could be alone here, but I never stop looking at job postings. If I ever see something more interesting than my current job, why not explore it. Chances are you would miss the most interesting opportunities if you weren't looking 90% of the time. The best time to search for jobs and interview is when you already have a comfortable job. Then your desperation doesn't force you to take something you don't love.
I like my job, but that doesn't stop me keeping an eye out for something better.
Imagine the flip side conversation: "We're thinking about firing you, so we're interviewing people. Not sure, we'll see how it goes. I suppose we might be convinced to keep you if you work an extra 20%."
It's an extremely asymmetric relationship. Recognize which side of that relationship you are on.
I would normally be reluctant to tell a boss that I'm looking. I'm pretty sure that I would never tell someone who could say this; in fact that there's a good chance that person might already be driving me out, whether I was good or not.