[anonytrary]

Agreed. Everyone should aim to have 3-4 spikes they are passionate about. For every spike you have, you become exponentially more of a domain expert at the problems that are at the intersection of those spikes.

[PeterisP]

Yes, proper senior expertise often looks like being a jack of all trades and a master of three or so.

[atla-sh]

Another perk is that you have other spikes to grow for variety to keep you from burning out or becoming disinterested.