I have urine incontinence and I have read a lot about how to perform the prayer correctly. The problem is that I know you have to use an absorbent, but do you have to change it every prayer time? So you use one absorbent for Fajr. When zuhr comes do you change the absorbent or can you re-use it although there is urine on it?
Usually I use a tissue as an absorbent, but I go to college, and so when it comes to performing the prayer, I cannot easily change the absorbent as I don't carry enough tissue with me and there is no tissue available in the college sometimes. Also, I do not have sufficient time to change the absorbent. Can you please give me extensive details on how to perform the prayer correctly with a problem like this for I want my prayer to be accepted by Allah the Lord of the ‘Aalameen.
Another problem is that when I urinate, for at least five minutes from the time of urine, every 20 seconds (appx) a drop of urine comes out (For the rest of the day, drops of urine come out at random which I cannot predict or stop). Am I allowed to do wudhu at this time and perform the prayer, or do I have to wait for more than five minutes and then perform ablution? Usually, when this happens (when I urinate in mosque) I miss the congregation in mosque.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

Firstly, you should cleanse yourself thoroughly after defecating or urinating making sure that no impurity remains on your body. Immediately after cleansing, put on an absorbent. After that, you should perform ablution for every prayer at the beginning of the prayer time. You can pray the obligatory prayers and any other supererogatory prayers. Having done this, anything that comes out is negligible and does not have any effect on the validity of your prayer even if it comes out while you are praying. When the time of the following prayer comes, you should cleanse yourself again thoroughly, removing any impurities that might have touched your clothes. Perform ablution and pray. If removing the clothes and the absorbent causes hardship to you, then you only need to perform ablution and then pray. 

Know that, if you have the usual pause during this discharge before the fixed time of the prayer ends, then you have to wait until that usual pause passes, cleanse yourself from it and pray. However, if you fear that the fixed time of the prayer will end before that usual pause, then you have to perform the prayer even though the discharge continues as mentioned above. It is better to perform each prayer at its fixed time than to join them because of this problem.

For more benefit, please refer to Fatwa 365380, 343018, 344443, 354916, and 361150.

Allah knows best.