Rated 5F. Does it get below 5F where you are?

It sometimes gets below 5 in z8, so 5 is certainly possible in z7. Not often, but sometimes may be enough to spoil a planting while you are still around. Example is decimation of camellia collection at National Arboretum (in D.C.) by hard winter, after many years of success. Looking at their web pages they apparently decided not to replant similar, "tender" kinds as a result. Should a home gardener take the same approach, or is perhaps decades of enjoyment from a possibly marginal plant selection adequate compensation?