2005 Pacifica clicks but eventually starts
 

2005 Pacifica
If the engine has not been run for a few hours or more, when the key is turned there is a "clicking" noise. The vehicle has a new battery and all electrical systems work. It always eventually turns over, sometimes it takes only 3 or 4 tries, sometimes 40. Every time you turn the key it clicks until eventually, with one of the key turns, the engine turns over.
It has been doing this in the winter and summer - ambient temperature doesn't seem to affect it. If the engine has been running, it doesn't do it. But if it sits and cools at all, the problem arises again.

fast clicking or single click or clunk?

A single click with each key turn.

Starter solenoid contacts are likely to be the problem.

Is that a complete replacement or something that can be fixed on the existing starter?

Starter itself is pretty robust, contacts not so much. Many people pull the starter, replace the contacts and plunger.