I believe wireframing should be approached differently depending on the situation, timeframe and budget, but should always exist as a way to fast iteration even if it is in sketch form.
Usually I start by sketching some low fidelity Wireframe with pen and paper. This sets the work basis to have a quick visualization or else we can overthink things and waste too much time. In later iterations I set them in high fidelity if needed.
The level of detail also depends of project necessities, just setting hierarchies, spaces and composition or even defining copy.
The tools used may vary. I can use Illustrator quickly as I can also use software like Balsamiq or Axure.
Wireframes for a telecom gaming app. First sketches. Set a quick base for discussion and next iteration.
Mobile e-Learning platform. Concepts and first wireframes.
Detail screen of a flight management system. Desktop web app.
A virtual sticker collection app.
Navigation flow for a product scanning app