In a townhouse, you'll typically only have neighbors on either side, as opposed to on all sides if you live in a condo. But that doesn't mean you want an amateur heavy metal band practicing in a room adjacent to your own at 2 a.m. – especially if they're absolutely terrible. So you'll want to explore how easily noise travels through the set of townhomes you're considering cuddling up into. The so-called party wall doesn't mean you're interested in joining the party, after all.
You can do a little P.I. work – and potential future-neighbor-friendship-building – by asking others in the row how well their townhomes are soundproofed and what the tone of the neighborhood is. Do they hear others' TVs better than they hear their own? Are transportation sounds an issue? Or is noise pollution at a minimum? If you fall into a sleeping state that others would equate to being a plank of wood, you're good; if you're a super light sleeper and your community is a loud one, you'll regret this decision the first day you show up to work and people think the zombie apocalypse has begun.