We took out a home equity loan to put an office addition on the back of our house. It wasn't difficult but I like advice
@barkley gave you about getting advice from a realtor. Our neighbor died at 95. He had been a widower as long as we've lived here, soon to be 28 years, so we never knew his wife. Neighbors say he lost all urge to do anything, including keeping up on his home, after his wife passed and rarely came outside.
When I saw pics of it online, I was floored. It was like stepping into 1964. It had the same oven and dishwasher we had in my earliest memories (I'm 57.) Amazingly, they still asked $520k for it, as is, and it sold in one day. If it were updated, it would have gone for probably $650k. It definitely needs at least $100k in work.
Anyway, they still got a good amount for it and all they did was empty it out.
Depending on the condition of the home, realtors know which homes will attrack flippers, or if it doesn't need everything, they could give you tips on the most important items to replace, how to get the best bang for your buck.