PPF: When do you ink?

Hi and welcome to my entry for Paint Party Friday! I'm on vacation, traveling abroad for a month, and my art kit is limited to a sketchbook, watercolors, watercolor pencils, pen and pencil. I've enjoyed the opportunity its given me to explore this media.  When I first started sketching and painting with watercolors, I would sketch with pencil first, then paint and then add ink at the end to define everything (like I did in the bottom picture above of hurling equipment left outside a store on Innis Mor). Recently, I've experimented with sketching in pencil, then drawing in ink and painting last (like I did in the Insomnia Coffee Co. sketch). I find this easier and much more free-ing. It's almost like coloring in a coloring book!  Finally, I've made a few pages like this:

where I do some free painting without pencil or ink guides for large parts of the piece.  I find this scary! So, I'm curious, when do you add ink to your drawings/paintings? 
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