I think your old boss's meaning was pretty much the opposite -- 10 years of deep experience in a field can be much better than 10 years spent hopping around fro

I think your old boss's meaning was pretty much the opposite -- 10 years of deep experience in a field can be much better than 10 years spent hopping around from job to job across fields. Applied to programming, this would be something like "I want someone who has been doing ML for 10 years, not someone who has been hopping from hot trend to hot trend every year and just now happens to be doing ML".