Ask HN: How common is it to plug full time gaps with contractors?

I've seen it happen a few times a year with my clients in London. Occasionally the contractors become part of the furniture though as good candidates that are available at the right price are not always easy to come across.

It's common in London in areas which have a shortage of good candidates.

It is generally not a good plan to fill gaps via contractors because you "couldn't find any good candidates". The process of finding contractors is largely the same as finding FTE and they have some added overhead/moral hazards.

You can use contractors if you have timelines that require bringing them on fast, or limited scope work. Any situation that requires the long term use of contractors is suspicious (and potentially problematic from a legal/tax consequence).

I think the logic behind hiring contractors is that he's available to start working immediately and, in the meantime, a company can look for a good permanent employee (which is usually much cheaper as well, at least in London) to replace him.