I visit Malaysia on weekends but not every weekend. I go there once every few months for good and cheap food, services such as massage, pedicure, manicure, hair cut and colour. Services are generally about half price of Singapore which makes it worthwhile to travel over.

Clothes are also cheaper at Malaysia than Singapore. Clothes in value in Malaysia is the same as Singapore but in RM! Due to the exchange rate, price is about a third of Singapore. There is also outlet at Malaysia which makes buying branded goods easy. 

I do know many Singaporeans go over for grocery shopping and to pump petrol. I don't do both as I find it risky to drive in and grocery shopping is too heavy to try to carry it over the causeway using public transport[Facepalm]