Is there a problem with using new filler on top of old body work?

Thanks

Others may post and say "I did it and never had a problem"
If it is a beater, and you are going for the cheapo paint job, just to make it shiny, go ahead.
If you are spending BIG bucks and many hours to make this a special car, NO WAY!
When I do my stuff I take it ALL the way down. I don't want to live with what someone else, may, or may not have done.
The older formulations of chemical fillers do not hold a candle to todays products. Why put all that time, money, and effort over a product that you are not sure of.
If it is worth doing, do it right.
Karl

Ditto..on the above post...