The attachments included with your indoor vacuum cleaner should serve as a guide of sorts to what kind of outdoor mess you can clean up. If it doesn't easily fit through the end of the tube, you shouldn't try to force the issue, no matter whether you are inside or outside. Some small debris on the deck is probably not much different than dirt or lint you'll find inside the house, though take care to not force twigs, branches, or other sharp-edged yard waste into your vacuum.
Most indoor vacuum cleaners collect debris in a paper or material bag inside the body of the appliance. Assuming you give the outdoor area you intend to clean a quick sweep first, the bag won't fill up any faster than vacuuming a well-traveled living room carpet. If you attempt to get into larger yard waste piles, you'll likely find the holding capacity of the bag quickly exceeded. Eyeball the outdoors area you want to clean first, and decide if it is roughly comparable to an indoor mess or if it goes far beyond that.
One area where many traditional indoor vacuum cleaners do not perform well is in cleaning up liquid messes. The same goes for a liquid mess outside. If your vacuum bag is made of paper, it will soon begin to deteriorate, and then the whole process goes awry, with no place to hold vacuumed debris. If you have a liquid mess, whether it's indoors or outdoors, you'll probably need a wet/dry vacuum for the job.
When deciding if you should use your indoor vacuum on an outdoor job, your primary consideration should be what type of debris it is rather than where it is located. Your vacuum cleaner does not care whether you turn it on indoors or outdoors. It doesn't even care if you try to suck up a mess that goes far beyond its capabilities in size and scope. The point is that if cleaning up whatever mess it is with a vacuum seems like a bad idea, it probably is, and you just might end up with a broken vacuum cleaner.