What is the ruling on fasting the days from Monday to Thursday of every week, including Tuesday and Wednesday?

Fasting four days is a good deed for which the doer will be rewarded, provided he can observe it consistently without interruption. However, if he fears boredom and abandoning the fast, then he should limit himself to fasting Mondays and Thursdays, because the deeds most beloved to Allah are those done regularly, even if they are few.