I think that having some cash put aside for the house is a good idea. However, as regards to the amount, it can vary and most can be planned. For example, standard roof shingles last about 15-25 years depending on the brand and the cost of replacement can be planned. Or a hot water boiler around here only lasts 6-10 years ($500-600). Otherwise, if something expensive happens, like flooding in your basement, then home insurance will most likely cover it.
I personally don't have a fund set aside specifically for home repairs. If something were to happen, I would simply use my cash stash if I needed to do repairs or pay the home insurance deductible.