Why do Formula one cars have to keep the same livery thru out the season?

May be...

because of the sponsors, and usually they pay a lot to have their brands on F1 cars for a single or multiple years, so you can't imagine a car with a diffrent livery each Grand Prix

a team may lose or gain a sponsor throughout the course of the season... hence these sponsors may appear ... or disappear during the course of the season... hence there may be slight changes in the details...however the general appearance of the livery is retained...

eg : Virgin wasnt displayed in the Brawn during the first race , but after its stellar performance, Richard Branson immediately got on the bandwagon and became a sponsor ... hence Virgin was displayed... but only after the first race...

becuss that is important

formula one teams have the same sponsers all year, they dont change from race to race like nascar. They have contracts with each sponsor for that year so they have to keep the same livery. In the case of ferrari, marlboro owns the rights to all the space on the car, but then they sell space to other companies that want their name on that car for the year.kd 30xs955 best buy