Without more facts, I cannot give you an answer specifically related to a particular person.
In general, though, pre-trail, detention is approrpiate when if can be shown that the accused may try to avoid prosecution by fleeing or hiding or that the accused is a danger to the alleged victim or to society in general. It may also be appropriate when the accused allegedly commits new crimes while out on bail or probation.
It is not possible to answer when pretrial detention is appropriate, because what is "appropriate" differs from person to person.
With that said, take a look at Florida Statute 907.041 (http://www.flsenate.gov/Laws/Statutes/2011/907.041), which details when the State may seek pretrial detention. Ultimately, the decision to detain (instead of release on a bond or on their own recognizance) someone pretrial is going to rest with the judge.
Most commonly, you will see it if the accused was already out on bond and that bond was revoked because the accused either committed a new offense or violated another condition of release. You will also see if often if the charge is a felony punishable by life, or some other circumstance where the accused isn't entitled to bond such as a violation of probation. In most cases, however, a person is entitled to reasonable bond.
Responses should not be relied upon for legal decision making. One should contact a lawyer and establish an attorney-client privilege to rely on legal advice. Any communication here is NOT considered attorney-client privilege and is not confidential.