Definitely! That's one of the beauties and probably the main reason why people go modular, it's all done at your own time. Take as long as you want, work when you want, fly and study when you want to. 16-18 months is an estimate full time modular but you can space it out over many years.
When ever I asked my school for a time frame I'd always get the same response, nobody knows. Weather is the reason why. Done my PPL in 6 weeks start to finish, took other's on my course 4 months and probably had about a month of no flying in between due weather. So it depends on you - the effort you put in, you're ability and weather.