Ideally (i.e., with persistent practice and under proper guidance) one should achieve basic level of mastery in 3 years (see the next FAQ below on the different stages of tai chi learning). Note that this is already fast by all accounts. It’s probably unrealistic to expect to build up a solid foundation of any tai chi styles in less than 3 years. Also note that simply learning the forms (which can be undertaken in a few months) without understanding the internal requirements amounts to not much more than learning some relaxation exercises, not the true tai chi. As Master Liu likes to say, “there’s no tai chi.”