My mother and grandmother are both avid bakers, and as I get into it more I hear different things from each. One thing they disagree on is whether or not the crumb coat is necessary or if its a waste of frosting? Love to hear opinions!

I crumb coat every cake for several reasons.  First, it truly seals in the crumbs which makes getting a prettier smooth finish easier.  Second, it helps me make sure my cake sides are even.  It also helps seal the bottom of your cake to the cake board.  In all honesty, I have iced cakes that don't have smooth finishes without crumb coating, but NEVER a chocolate cake.  Always crumb coat those!

Not sure how crumb coating can be seen as a waste of frosting?  It is such a thin layer and the amount used for the crumb coat would most likely still be used if not doing a crumb coat.

Anyways, I like to crumb coat because then I do not have to worry about accidentally bringing any crumbs into the finish look.  Then again I am a messy frost-er (?) so eliminating one thing to worry about as I slap buttercream on my cake is always a plus.

Ditto to all of the above.  I have frosted many a cake without crumb coating and it works pretty well for a cake that has few crumbs, but I far prefer the crumb coating method.  I really like finish icing a crumb free, straight, smooth, COLD and stable cake.

i rarely crumb coat -- always seemed like extra work to me -- but when a cake might be excessively crumby it is a nice method -- live red velvet for example -- 

here's one of my favorite sayings -- "one baker's never ever do is the next baker's i swear by this" -- ain't no wrong way if it works 

I like to heat my icing to spread on a cake as a crumb coat.  Just enough to melt it in the MW it just takes a few seconds - of course depending on how much you are going to use.  Mostly you only need 1/3 to 1/2 cup and that takes less than 10 seconds to melt it.  Then you need to work quickly to spread it all over the cake.   Any leftover is not usable for anything so don't melt more than you think you will need.  This makes a much better crumb coat - it dries fast - a more solid covering &  don't need to frig'd before starting finish coat of icing because it dries by the time you complete the crumb coat :) 

Well, I never!  I've never heard of that method of crumb coating, kakeladi, but I will surely give it a try!  Like I keep saying, you and Kate are the cake fonts of all knowledge!

I was too chicken to try that! I've melted BC before, but never crumb coated with it.  I will now though!  I learn something new everytime yall answer a question...thanks all of you!