When replacing the tie rods, some have considered replacing just one tie rod (inner or outer) to save on the tie rod replacement cost. However, most technicians can agree that swapping out both tie rods at a time - even when one of them is in mint condition - is the most ideal approach. There are a few reasons for this. For starters, if you need to replace the inner tie rod, you'll first have to remove the outer tie rod to gain access to it. So, you may as well replace the outer ones, too. On top of that, the inner and outer tie rods are a part of the same system. Therefore, replacing just one and not the other creates an unbalanced system. In short, it could allow the unchanged tie rod to put more strain and wear on the brand new one.