Gugi99: I always tell my sellers of the "bright penny" rule. If you show a little kid a group of coins, the child will usually take the brightest one. Same with roughly equivalent houses. If the bright house goes, there may well be another on the market next week, putting right back in the "less desirable " category. I spent $30,000 on my own (rather jaded) place and then got top dollar fast. You really do need to freshen the place up.
So much for generalities. If by staging you mean a professional interior decorator type, hired at a significant cost, after the usual clutter and scraped-up walls are painted, it all depends. If you have a luxurious address, you may find it worthwhile. If you have little aesthetic taste and feel helpless, it may also be worthwhile. However, you real estate agent SHOULD be able to tell you how to arrange what you have attractively. After all, they see a ton of homes and unless they are totally clueless, should be able to make some attempt at good advice on that basis, if no other.
While I always say that the average person has no imagination, so you don't want to leave the "bummer" image prevail, they also have specific taste and if all the fancy stuff doesn't strike their fancy, you've spent money for nothing.
My advice: Unless you can at least see that the stager's fee will result in a better return, I'd tend toward a "do it yourself" approach. That said, a neighbor of mine make a great living as an interior decorator to the very wealthy, even down to their yachts!