No, it completely depends on what sort of appliance you are talking about.
You will have to look and see what the voltage range is of your appliances. In Argentina there is both a difference in voltage and hz (hertz/ is it?). Most NA appliances run at 110v and 60hz cycles. Here it is 220v and 50 hz cycles. Most equipment these days will not be affected by the cycle difference, but you may notice that your hair dryer from home runs a little slower etc.
It's important to know the voltage and hz of your equipment however as this will affect whether you need an Adaptor, a Transformer, or both. An adaptor is simply a dummy plug that allows your NA plugs to plug into the wall, it does nothing to change the amount of power your appliance receives. A transformer is a box that plugs into the wall and you plug your appliance into that -- it slows/increase the current -- don't ask me how I'm neither an electrician or a physicist. You will have no problems with this and most are transformer/adaptors. You can use one of these for the long term no problem.
Some products, such as laptops, work in the full range 100-240V, 50-60 hz and these appliances require only an adaptor (if that -- computers here take the same grounded plugs as we use in NA so I can just plug right in). Some small appliances such as hair dryers have a switch to change from 100 to 220 -- you must change this or you'll kill it! -- for these types of small appliances with the switch you will also just need the adaptor.
Other appliances (and mobile phone chargers, as I learnt the hard way) do not have a switch for the voltage. This means you need a transformer AND an adaptor. For instance, if your bringing things like blenders I suspect that there is no magic switch and you will need a transformer so you don't blow the circuitry.
Any of your appliances should have the voltage displayed on their base or somewhere else on the battery. A lot of "mobile" equipment such as laptops have overcome this by creating batteries/motors that can work in the full range. However, as I say my mob charger didn't -- I blew it plugging it in here, I should have used a transformer for it.
By the way, depending on what types of things you're thinking to bring it may well be a good idea -- a lot of electronic products can cost considerably more here than in America.