Do braided stainless steel hoses with surface corrosion require replacement?
It really depends on the type of corrosion, some may be more surface finish failure and the hose can last for many years if not a decade. I have seen rusty lines that have some of the strands breaking and the line was not leaking not yet, I would suggest once the outer braid starts failing it is time to replace the line.  the urgency would be based on several factors like is the line disturbed or bumped my wife has a buck she stores under the sink that bumps the line in that case it may need to be replaced sooner than one that is never touched.  The pressure is also a factor, if you have less than 60 psi I would not be as concerned compared to a home with 90 psi. The last is personal opinion, some want to replace for any reason others may wait for a drip and each opinion is probably based on past experience and disposable income.