I have my own strategy to save money for a long time period like managing it when it comes to spend it and also save it in the bank but for me is I save it and I will forget that I have money in the bank that's why I save it more and especially if I needed it I have another reservation for my money in investing.
each person have their own strategy to make their money growth.they can use it on investing portofolio or save it on bank.choosing investment portofolio need some research and observation in order to get best portofolio.
I guess if you don't want a big increase, you have to save it in the bank. it's the only way to save in a safe way for a long time. Well, investing is really good, but it makes the risk even bigger.