Help please

This is what I have been using to track ovulation, only being doing it for 2 months so I am new to tracking. I had a missed miscarriage in January and I now want to know when I am ovulating. My question is with this ovulation tracker can I use the machine for more than 1 month? The first kit I bought came with 20 tests and I only used a handful so I used the same kit again the following month. The cycle day of ovulation wasn’t anywhere near the same first month 1 and 2 and now I am wondering if I need to buy a new kit every month? Any help would be appreciated.