"When will you be done with the house?"
Instead ask: "What's your latest home project?"
Why: No need to put pressure on somebody who's in the midst of fixing up a fixer-upper. It's about the journey, not the destination. If you're curious about how the renovations are going, ask about the project they're thinking about or working on right now.
"How much is your rent?"
Instead Ask: "Do you think rent is reasonable in this area?"
Why: If you're asking because you're in the market, the re-write is a much more tactful way to go about getting the low-down on market rates in a new neighborhood. If your conversation partner wants to offer up what they pay, they'll do it here. If not, they might have some great insight into an affordable building or a great broker.
"How much did you pay for that?"
Instead ask: "Do you have any secrets for getting a good deal?"
Why: You're probably asking how much a thing costs–the sofa, a TV, their new range–because you suspect it's expensive, yeah? And you're wondering if you might be able to have something so nice? Instead of putting your conversation partner on the spot with their finances, ask if they know any tricks to finding a good bargain. You might find out about a great sale or out of the way second-hand store.
"When are you two having kids?"
Instead ask: "What's next for you and your husband/wife?"
Why: This question can be really harmful to a couple that is trying to conceive, and it's somewhat annoying to couples who choose to be childless. If they want (and can have) children, they'll talk about it. But they might also open up about their wishes for a future home, pets or a dream vacation.
"Do you have a boyfriend/girlfriend yet?"
Instead ask: "Who have you been hanging out with these days?"
Why: Not everyone's just walking around trying to figure out who to shack up with next. And even if they are, no need to remind them that it's not going so well. If they're smitten with a new someone, they'll tell you. If not, they'll mention their great group of friends or some coworkers they're happy to have gotten to know recently.
"What do you do?"
Instead ask: "What's been keeping you busy?"
Why: The work question inspires awkward vibes when asked to somebody who is un- or under-employed. The re-write gives people an opportunity to share what they're really excited about lately–school, children, hobbies–without addressing anything they don't want to discuss.