Praise be to Allaah. If you pass urine or drops of urine, this does not mean that you have to do ghusl; what you have to do is make wudoo' and wash only the parts of the body and clothing (on which the urine has fallen).
If the situation you describe, the occasional emission of a few drops of urine, is beyond your control, then your case is like that of one who is incontinent, so do the following
1. Wash the private parts with water.
2. Wash the part of your clothes that the urine has gotten onto (there is no need to change your clothes).
3. Put a pad or a piece of cotton, or something similar, over the private parts so that the urine will not spread.
4. Do wudoo' for each prayer, then pray as you are, and pray as much as you like, fard and naafil, with this wudoo'.
After doing this, anything else that comes out does not matter.
Allaah says (interpretation of the meaning): "So keep your duty to Allaah and fear Him as much as you can…"
Do not miss any prayers or delay doingthem on time, and your prayer will be valid.
This is what should be done in the case of incontinence, but if the urine comes out shortly after urinating, then it stops, in this case you can go to the bathroom fifteen minutes before the prayer or the adhaan, for example, then put something (a cloth, etc) to prevent contamination after you do istinjaa' (cleaning yourself after relieving yourself), do wudoo' and pray.
And Allaah knows best.
Sheikh Muhammed Salih Al-Munajjid.