Comment by jarito

A quick google puts the tech annual turnover rate at 13% - 25%. Let's assume 10% just to be safe. Let's also define 'senior' engineer to be a Software Engineer 4 and above (so not 1-3) - that seems pretty common in terms of titles.

If you have a 100 person eng team split into 10 person teams. You will likely need one to two senior engineers per team. That means you are probably replacing 1-2 a year.

Now scale this to a larger company. Amazon has 100k engineers, Apple has 40k - 50k. Even outside of tech, Chase bank has 60k, even Target has 5k.

At the low end of that, a 5k engineering team (still assuming 10 per team and 1-2 of those are seniors) will have 500 - 1000 senior engineers. If they are attriting at 10%, then we would need 50 - 100 senior engineers a year. Hiring senior talent usually takes 3 - 9 months, so you'd easily need 10 open recs all the time just to keep your team at the same size.

This is pretty generous. Given remote work, the % of senior engineers has gone up, a 10 person average team size is still high, and I used 10% attrit which is low according to the average. Most large companies have large eng teams these days :).