What is the shelf life of a cake frosted in buttercream?
3-4 days or 5+ in the refrigerator ?
1-2 days room temperature?

I depends on the ingredients. A scratch cake will go stale much sooner than a box mix. The box mix has preservatives.

For a scratch cake.

Mine are all different. After three days, anything with bananas will get very strong. If I brush a cake with alcohol or use a cooked custard fillng, the cake will be good for a week. Heavy cakes that are very moist... red velvet, carrot... keep for days. The more delicate cakes seem to dry out the soonest. For the icings, I usually refrigerate with plastic wrap covering the cut edges and I cover the cake. All of my icings are european buttercreams or custard based. If they are for a customer, I box it, cover the top seams in the box with plastic wrap, and refrigerate. I take the plastic wrap off before delivery. At that point, the cake will be perfectly room temp for the customer.

Okay i was curious, to know thanks a lot. I do realize the more delicate ones tend to dry out a lot faster.
I asked because a customer came back after four days saying the cake was dry, she got the cake on Sunday afternoon and she said it was lovely and moist.
Now today she calls and says its dry, so I asked how she was storing it,
She said she cut the cake up and then just put plastic wrapped the remainder and put it in the refrigerator and now its dry.
I just have a feeling she didn't store it properly.

Most scratch bakers say to enjoy the product the same day as delivery. If she got three days out of it, that is good. In my opinion, scratch cakes are best about 12 hours after icing for the melding of the flavors. After that, most will lose a little quality every day. She may bake box mixes and she is used to a longer shelf life. I don't have this on my site, but a little explanation and storage tips for scratch cakes would be good. Thanks to your question, I'm going to add it now.

CWR41, we must have completely different recipes. I would not keep a cake on the counter for four days.

Most of mine are heavy, and please don't think I am disputing you. I think our differences may be due to bakeries with a primary wedding business have developed recipes that are more durable. You have probably developed recipes that will be better in a few days because that is your serving time.

My cakes are very expensive and I cater to a very discerning clientele. Because most are not wedding cakes, I feel I need to have a recipe that is at its peak at serving time, usually some time that day. I take new recipes that I have decided to use in my business and I either leave them out or refrigerate them. I try to keep them the way I think the public would keep them. I just feel the taste gets stronger,where I developed the recipe to taste best after about twelve hours. I will admit I am anal about this. Wedding cakes are not my main concentration, but I still do everything at the last minute, because I us my regular recipes. I understand that this is not possible in higher production kitchens with multiple wedding cakes.

OMG you spent a lot of time on that. I was more wondering about your "isn't typically recommended" claim regarding professional bakers/decorators rather than the mishmash of Cake Central users...but even then, what one person swears by, another would NEVER do. LOL My personal experience in speaking with other professionals is that refrigeration IS typically recommended. Of course I've read people here say that their refrigerators dry out cakes...but I've never had any problems putting all my cakes in my residential-grade refrigerators nor the commercial reach-in in my bakery. Some of my cakes have stayed under refrigeration for 3 days without problems (be they in the reach-in or the refrigerated display case). I don't plan on commissioning a study on the moisture levels of cake pre- and post-refrigeration, but I'm quite sure that buttercream is an effective seal against the drying effects of the cooler...and fondant, even more so. My loyal, repeat clientele proves that for me, as the number one comment when they come back to order again is "Oh that last cake was SO moist!"

People on the fence who have no experience of their own should make a batch of batter, split it between two pans, bake them at the same time, fill and ice them, then keep one boxed at room temp and one boxed in the fridge. After a day, or two, or whatever, bring the refrigerated cake - still boxed - up to room temp, then slice from each cake and see if there's a difference between the two. That's easy enough to do.

It seems you are contradicting yourself quoting classiccakes...but no matter, your opinion is just that ~ your opinion ~ and in your little world, you say more pros do not refrigerate. In my little world, more pros do. *Shrug* So....we're reached the point at which we agree to disagree and move on. People will learn for themselves through their own personal experiences. Thanks for your input too!