Are there any preparations required before one undergoes laser or sclerotherapy for spider veins?

In general None, but you must have money. For those who are obese, one may want to lose some weight before the procedure. Anyone who is taking blood thinning medications should discuss this with their doctor before the procedure. If you are going for laser, avoid getting a suntan at least 4-6 weeks prior to the procedure. The laser can sometimes cause a permanent discoloration of tanned skin