Sometimes after I urinate, I feel like a small amount of urine remains in my private part (not the bladder) and due to its small amount, I’m unable to discharge it. Thus, when I do istibraa, I expect to see few drops being discharged however, sometimes, nothing gets discharged, I don’t see any drops leaving. So is my istibraa valid such that if I see any drops later on, I consider them pure? As a general rule, if I do istibraa and don’t see any drops, is the istibraa valid?

I always hear that if you “see” drops and you did istibraa, you consider them pure and if you did not do, you consider them urine. My question is, do you have to “see” the drops? Because in my case, I’m almost 100% certain that drops are going to be discharged, whether I did istibraa or not. So can I take it as a general rule, if I do not do istibraa, I surely am going to discharge urine and thus have to purify myself and change my clothes even if I did not actually inspect and see?

Assuming that I did not do istibraa, after how long is any discharge seen considered urine? Like for example I urinate then immediately take a 15 mins bath without doing istibraa, after I finish and wear my clothes, I see drops, is it still considered urine?