This is a good question. Part of the problem is that when you start to worry about balding you notice hairloss that you wouldn't have noticed before. For example, now when I shampoo my hair I look in my hand to see how many hairs are there, this is something I've never done in the past.
These days, when I have probably 5-10 noticable hairs lost in the shower, a few more on my hands when I apply minoxidil, and then 5-10 more in the sink after brushing my hair. I feel like this is more than in the past, but like I said I really am conscious of the hair I'm losing so that could be the difference.