Microneedling & Derma Stamp Longevity

I will be starting with once a week derma stamping next week with a Follicly Titanium Needle Adjustable Derma Stamp (I bought 3 of them). Each stamp has 140 titanium needles. My hope is that microneedling will further promote regrowth in my stubborn temples. I am likely going to start at a needle depth of 0.7mm and skip a topical treatment day when I stamp, and see how it goes... On non-stamp days, I use a daily application of Minoxidil 15% / Finasteride 0.3% / Tretinoin 0.015% topical hair spray on the temples and forehead hairline.

Q's:

1. How long should I expect a titanium needle stamp like this to last if used once a week (i.e. how many weekly uses will I get out of one stamp?) 2. Besides cleaning/soaking in rubbing alcohol before/after use, are there any other tips/tricks I should do to maintain the stamp for better longevity? 3. Any other specific recs for stamping temples for receding hairline regrowth from those that have had success doing similar on the temples?