Also known as an overactive bladder, this is the most common type for men. You experience a sudden urge to urinate and the bladder involuntarily expels urine. This is usually due to interference in the nerve signals between bladder and brain, often linked to either an enlarged prostate or the aftermath of prostate surgery.
You may also find that you need to urinate more frequently than the usual 4-8 times a day, and maybe also at night too. However, in certain cases you can 'train' your bladder to urinate less frequently and to avoid urinating at night.