An important aspect of practical classifiers is interpretability. Learning compact but highly accurate models that help in human decision-making is challenging. Most such simple scoring systems were constructed by human experts using some heuristics and are not optimal. In many prediction tasks such as medical diagnostics, there are many more challenges: finding optimal individual treatment; taking budget into consideration, and the budget (any finite resource such as time, money, or side effects of medications) in real-life applications is always limited. I will consider principled methods to learn interpretable simple rules purely from data. I will also show possible solutions to take the limited budget into account, and discuss some perspectives for development of methods of personalised medicine.