Beware of Stendhal syndrome, also known as hyperkulturemia, namely, dizziness caused by being overwhelmed by Florence's fantastic art. Yes, it's a real syndrome, named after 19th-century French author Stendhal, who suffered from it during his stay in Florence. If you get overwhelmed, rest your eyes and legs, get some food remember gelato, and save the rest of Florence for tomorrow.
Florence is generally safe, but take precautions against the opportunistic thieves common to major tourist attractions: pickpockets and purse snatchers. Savvy thieves congregate in crowds, particularly around Santa Maria Novella train station. If you have a pocketbook with a classy, noiseless zipper, it will be opened.Also exercise caution on buses: pickpockets can be active on crowded ones and, as everywhere else, they preferably target tourists.Occasionally, some types of beggars can be insistent and distracting while at the same time another thief quietly steals your wallet or phone. Again, this is nothing new to major tourist spots.
contact
Since there are a large number of tourists around, the center of Florence is brimming with webcafés and telephone call centers. Most evenings there are long lines for access to the phone-booths.
You can also buy a pre-paid card which will give you a steep discount on international calls by dialing a special number.
Wireless LAN access is becoming popular. Even when offered for free, you will need to provide your name and contact details to the provider of the service to obtain an access code. This is because of Italian anti-terror laws. Anonymous access is not possible.