I also suffer from diffuse thinning. To be honest, I don't think you can only maintain with finasteride, but you can always try 6 month to see if it works. If it doesn't work, you will need to add minoxidil, and if this still doesn't work (which is not rare), you will have to get on dutasteride, and even then, you might keep loosing your hair or maybe u stop it. I'm for example on oral dutasteride and oral minoxidil 3.5 mg (tried 5 mg with same results as 3.5mg), and it unfortunately didn't stop my hair loss (it has slowed it down at least so I'll borrow some time and wait for new treatments in the future). In brief, anything you take is better than nothing, because at least you will slow it down and have hair for a longer period of time