Is taking daily 250 vitamin c tablets to much? pros and cons?

No, it is not too much but it may not be necessary if you have a typical American diet which is often not deficient in vitamin C. In general, taking 250 mg of vitamin C a day is harmless but I still advise my patients so stay away if they have history of kidney stone. In contrast, for patients who take iron pill for iron deficiency then I advise taking a small dose of vitamin C supplement.