Excellent advice.
The time for an attorney is _before_ you sign the agreement for sale.
While such agreements are pretty much standardized, your attorney can make sure any special conditions necessary to protect you are listed and there is nothing to later come back and bite you.
Sorry to say it, but many real estate agents I've seen aren't very knowledgeable and its hard to find a true professional. When I bought my place the seller's agent had a bad but justified reputation for being a real pain and too aggressive, but she knew what she was doing and she was honest ("Is the building soundproof?" "No"). She made very sure I was ready for settlement -- that my mortgage, down payment, etc., were all in order and ready to go. She did phone me a million times to check, but she was doing her job. Many times one or both parties aren't properly prepared at settlement and its held up. When my parents sold their house, the buyer was unprepared and left their baby with my mother all day while they went downtown and got stuff. When I sold my mother's house I couldn't use the above mentioned agent, but I found someone good in the city.
BTW, my mother never got cable TV and I was worried that it would be expensive and cumbersome for the new people to run cable wires through the house. When cable first served an area, the companies wired for free to attract new customers, but nowadays they charge quite dearly for that. Of course, I presumed the cable would be as carefully and neatly installed as phone wires were. Nope. The buyer asked for permission to come in and set up before the closing and I let them (normally not a good idea), and I found they had the cable installed that day, a big fat wire poked through the side wall, not discretely up from the basement.
From that sale I learned how important it was to have even little things in writing. I had no use for the refrig, washer, and dryer and wanted to leave them behind for free. The buyer didn't want one of the units and a friend did, so I was gonna have him come in to take it out, but then the buyer said they wanted it after all or I was confused. I ended up leaving everything for them just to make it simple for me. There was also confusion over the furniture they wanted. Fortunately they were nice people and everything worked out ok, but normally these kinds of misunderstandings will lead to trouble.
While my mother was able to sign the initial documents, she declined suddenly and I represented her at closing under power of attorney she wisely prepared long in advance. Ironically, while at closing no one gave the POA a second thought even though I was selling a whole house, which is after all a major transaction. In contrast, in dealing with my mother's bank accounts of a far lower value, the phone company, Blue Cross, etc., they gave me a very difficult time despite my having the POA. The phone co simply wouldn't talk to me since her account was password protected; fortunately my mother had a good day and was able to talk to them and remember the password.
As a personal aside, I felt pretty lousy abandoning my mother's furniture for sentimental reasons -- it was what I grew up with and its loss brought home hard that my mother wasn't gonna get better. I had no room for it and other family members lived too far away and already had their own furniture. My mother's neighbors were extremely nice and helpful and took care of it for me; whatever nobody wanted would be carted off to charity and I know my mother would've been happy doing that. (Selling it would've been more trouble than anything I would've gained and emotionally painful).