Anki (http://ankisrs.net/ http://ankisrs.net/ and https://ankiweb.net/about https://ankiweb.net/about) is what I'm familiar with. All versions are freely availa

Anki (http://ankisrs.net/ http://ankisrs.net/ and https://ankiweb.net/about https://ankiweb.net/about) is what I'm familiar with. All versions are freely available except the iOS version ($25). I use it to memorize all sorts of things, including phone numbers (something I used to do as a kid before mobile phones), birthdays, vocabulary (English and other languages), and poetry. Reading a book and then taking a walk is a form of incremental learning. Reading a page and pausing to question yourself about what you just read is incremental learning (see Make It Stick: the science of successful learning, by Brown, Roediger, and McDaniel, 2014). SuperMemo is one way to go about it, but it seems like icing on a readily-available cake.