Front strut/shock goin bad

[Tedster]

My front drivers side strut is goin out I think cuz its a bit soft, the passengers side is very hard and tight... so can I just get the bad one replaced or do they have to replace both fronts? I dont wanna waste money and replace the good one. And what happens if I keep driving with the bad one? Will it mess up other stuff on the suspension?
Thanks.

[red95_240sx]

if its a diff brand, one side may be lower or higher. its strongly recommended you do both sides.