Lots of Sellers ask my opinion on what they can do to fix up their home to make it sell quickly and for more money. There are some general things that can be done to help but each home is different and unfortunately, there is no crystal ball to predict what buyer preferences will be. There are certain trends but who knows what the buyer of your home will be looking for.
Everyone has different tastes. People spend tons of time surfing through Pinterest and Houzz to get ideas for their kitchens. Would you put your money in dark mocha cabinets or antique white? Sometimes, I find it's better to leave what you have and price accordingly. This is for the more "big ticket" items because you are spending your money where someone may just tear it down and replace.
I find it's helpful to at least do some preliminary work and get a quote. People have no idea what it would cost to replace things. They may negotiate $15,000 off the offer when it would only cost $8,000.
I would spend money on anything that would send a "red flag" to potential buyers. Let's say the skylight leaked. You fixed the flashing on the roof at the seam of the window and it's no longer a problem. However, if you have drywall damage people will be afraid of it being an ongoing issue that will cost lots to fix. Get a professional to mud the drywall then get a zinsser primer at Lowe's or any hardware store to seal it and then paint it.
Actually, a fresh coat of neutral wall paint throughtout the home goes a long way and doesn't break the bank. It showcases the home as fresh and clean, bright, and well maintained. It also provides a blank canvas of sorts for the new buyer to decorate to their taste. I particularly like Early Morning Mist by Benjamin Moore.
I say replace what is obviously needed. Otherwise, you may list lower to compensate for the cost and then buyers will still negotiate low for them having to replace the item. Get the advice of a sales representative you trust. Overall, you want to make sure your home is clutter-free, organized, and clean.