I agree with Joe, and would focus on the types of things that he mentioned. Beyond keeping the lawn mowed and possibly trimming low hanging branches that would smack someone in the face as they walk around the house, the only things that I would worry about on the outside are those that affect the inside; such as whether the downspouts are directing water away from the house and whether the grading is sloped away from the house, both of which, if neglected, can contribute to a damp basement or crawl space. Otherwise, in my opinion, "curb appeal" is too often overstated, not to mention that what is appealing to one person may be appalling the next. And the same can be said for a lot of costly interior renovations. I know of one house not to far from us that sold about 15 years ago, then again a couple of years after that, and again a few years ago. It's a nice home, and just happened that each of the sales were due to job transfers, nothing against the house, but each time the very large kitchen was completely gutted and redone, not because it was ever shabby, in fact far from that, but because the new owners did not like the same things as the previous owners. And I don't know all of the details, but enough that I am quite sure I could have framed and at least closed in a modest complete home for what has been spent on the multiple kitchen renovations in this home. My advise is to take Joe's advice, address things that need to be addressed, otherwise keep it simple, and people will envision their own "curb appeal".