It’s one of the key features that drew me to using Sketch. The concept of the infinite canvas means the ability to start a new document and immediately start creating. No time spent deciding what size what I want, or trying to find an option large enough to get going. When designing for a specific context (such as a phone UI for example) then it makes some sense, but not when working on identities, illustrations and icons that make up the bulk of my work.
I also enjoy using my iPad Pro and Pencil to work through ideas, but in general, iOS drawing apps start with the same task that many desktop equivalents do. You can’t start drawing until you’ve defined a size.
Fortunately, I’ve found an app that doesn’t put this obstacle in front of you - Concepts. This feels especially key on the iPad. In apps like Adobe Sketch, it feels like you run out of space fast, and somehow the break to close it and create a new document is very jarring. It’s also easy to duplicate a sketch, tweak it and keep going until the idea is refined. With Concepts the ideas and iterations can keep flowing, and that’s how I like to work.