If you're stopped in Florida and the officer believes that you may be intoxicated then he will likely request that you perform field sobriety exercises in order to "confirm or dispel" his belief that you should not be driving.
The key word in the above paragraph is REQUEST. The officer cannot force you to perform these field sobriety exercises. The roadside tests are not mandatory and it is always a bad idea to agree to perform them.
These tests are nearly impossible to pass - whether or not you have had something to drink. How often do you stand on one leg, count to 30, and keep your balance without lifting your arms from your side while a policeman shines a flashlight in your face? Yep, never. You cannot practice for these things and you're going to fail. The officer makes a subjective judgment call as to your success and you had best believe that if he thinks you're drunk enough to take the roadside test then he is going to arrest you regardless of how well you believe you performed.
Need another reason to refuse? The officer does not have an interest in whether or not you are truly intoxicated - he already believes you are. His goal is to BUILD EVIDENCE TO USE AGAINST YOU AT TRIAL! Yep, all of this work that you are doing to attempt to help yourself will be held against you when your trial rolls around.
So, what should you do if an officer requests field sobriety exercises? My advice is always the same: if the officer is requesting these tests then he believes you are intoxicated and you are going to be arrested whether you agree to perform the tests or not. Why supply him with evidence of "lack of balance" or "inability to follow directions" to use against you at trial? Just say no....and then call your DUI attorney.