Lovec1/Shutterstock The consensus among mechanics and finicky car owners is to replace brakes, suspension, and steering parts in pairs. For instance, it's always a good idea to replace the brake pads in, for instance, the left and right front wheels rather than just one or the other, and you'd want to replace struts or shocks in pairs or in sets of four to ensure balanced handling, braking, and steering characteristics. The same rule applies to the inner and outer tie rods. Although we're not insensitive to price hikes and would rather keep costs down by not messing with parts that still work, there are convincing reasons why you'd do better in the long run by replacing both inner and outer tie rods at the same time. It's not mandatory to replace both when one or the other seems fine, but replacing bothis what most experts recommend, since the tie rods (as a whole, including the inner and outer parts) absorb all the nasty impacts from bumps, potholes, and road irregularities while being constantly exposed to heat, rain, snow, mud, dust, and other contaminants. The tie rods connect the steering rack to the front wheels of your ride, and each tie rod has an inner and outer part. The inner tie rod connects directly with the steering rack. The outer tie rod connects with the inner rod and attaches to the steering knuckle. From that alone, it's no surprise that replacing both when one goes bad is usually worth the extra time and money. Why replace both inner and outer tie rods? Vasil Dimitrov/Getty Images For starters, it's not easy to pry away the outer tie rod from the axle. You'll either have to hammer it loose or apply heat to the jam nut before loosening. Mechanics do it all the time, but there's a risk of damaging the parts while doing so, and novice DIYers are just one wrong move away from turning a basic repair into a more serious one. Moreover, the locking nut holding the outer tie rod should be replaced after loosening, since it is not designed to be reused after removal. And here's the kicker: You'll have access to both the inner and outer tie rods after loosening the latter. After all that hammering and elbow grease, it only makes sense to, say, replace the outer tie rod even if you're only planning to replace the inner tie rod, and vice-versa. And remember that stubborn jam nut? There's a huge chance of stripping the threads while loosening it, and it so happens those threads are on the inner tie rod, especially if the part has some rust in it (which it probably has). Lastly, the inner tie rod has a rubber boot that deteriorates with age. If you happen to find out the boot is torn, shredded, or damaged, you'll need to replace it along with the inner tie rod, even if the initial plan was to only mess with the outer tie rod. How to know when tie rods go bad Corrigan201/Getty Images Keen drivers will find it hard not to notice when the tie rods of a vehicle are loose or worn out. The initial symptoms are uneven tire wear, alignment issues, and a somewhat loose, wandering steering feel. You'll also feel some vibrations or shaking from the steering, especially when accelerating, and some pulling is expected when the tie rods go bad. Either way, those are telltale signs of imminent suspension failure, and some of the symptoms can be attributed to other failing parts, like worn bushings or control arm ball joints. Furthermore, clunking noises from underneath when turning the wheel are classic signs of bad tie rods. If you're in a bind, it's relatively okay to replace just one tie rod, but only if you're certain that the other is in tip-top shape. The parts would typically cost $100 to $400, but luxury cars and large crossovers would cost more. Talk to your mechanic if you have doubts, but they'll almost certainly recommend swapping tie rods in pairs and insist on a wheel alignment after the repair.