If the sofa is bordered by a pathway on either side, you will need at least 70 cm to walk comfortably past it. Of course, you may not have this space available, so consider whether sofa or transport comfort is more important. For example, if it's an infrequently used route and you live in a two-person household you may want to opt for the sofa, but if you live with a lot of people and it's a busy route, you may want to opt for transport, because in a smaller space two people can only fit sideways if they bump into each other.