Hi Sparkle,
Excellent questions. Some women prefer to have a very natural look to thier lashes, almost a lash tint rather than anything that lengthens or thickens. If that is that case, alot of women will take some product off the mascara wand before application. I think it would be more sanitary to use a clear mascara or a mascara like Maybelline's Define-A-Lash which imparts a more natural looking mascara. The reason I wouldn't always wipe the wand on a sponge or tissue is because if the wand gathers fibers, or the sponge touched the surface of something that has bacteria, you could transfer this to your lashes, or it might stick to the wand, go back in the tube and collect more bacteria. Yuck! However, i'm not knocking your sisters technique, I just think that there are other, slightly more sanitary ways to go about it

As far as re-using a makeup sponge, are you referring to the ones that are in your powder compact, or ones you pull off of a larger square to apply liquid and cream foundations? For the ones in your powder compact, I tell my clients either use a new one each week, or wash the one you have thoroughly with anti-bacterial soap or face wash ( I would prefer replacing it, but if that's not in the budget, it's understandable.) The bacteria that collects on the sponge could cause blemishes on the face.
A trick I like to share is instead of buying liquid liner and possibly encounter bacteria growing in a tube that is a couple of months old, buy a black cake shadow or liner (try Yaby's cake liners at
www.yabycosmetics.com) or Benefit's Babe Cake (
www.benefitcosmetics.com) and use an eyeliner brush with a saline solution or eyedrops. Keeps it nice and sanitary and gives a great look.
I'm sure many of our members have great tricks, and I as I think of more, I will post. I want to hear what
your tricks are too!