I look after my kit very well, so therefore shouldn't need a filter.
BUT I have kids, and kids like to touch things with fingers, pencils, pens, and other scratchable materials!
So a £20 filter on a £150 lens is small change compared to maybe having to replace the lens.
My 18-55mm has a UV filter on it, and I've had to change it once already (only had it since April) - little one managed to scratch the filter with a lego brick (by accident mind you)
I've said it before, and I'll say it again - for my photography skills, adding a filter does not affect IQ.
Best way for you to know - try with and without one on