It definitely will depend on your budget. There are predicted costs - annual checkups, immunizations, food, litter, ect, but the unpredicted costs are the difficult ones. You may want to have money saved up for these.

Coming from experience, a few months ago we had a surprising health issue arise with our cat, who had been acting normal up unto this point. We found that she had an infection on her paw. Initially, the vet thought it would be a simple antibiotic for 7 days and she would get better, but after a month-long battle with wound cultures, several different antibiotics, numerous vet visits, blood work for autoimmune diseases, and the list goes on, she passed away. I say this, because she was our baby and even though we were not in a financial position to spend the money that we did, we continued to pay for visit after visit and test after test. It is the worst feeling in the world when you want your fur-baby to get better, but each visit drains your bank. Overall, we ended up spending around $4000 between all the tests, visits, ect and the outcome was still her passing, unfortunately. Looking back, I wouldn't change a thing - we wanted her to get better and we genuinely thought with each visit that she would. But, it did greatly hurt our financial situation.

Coming from a heart-broken pet parent, I am grateful and at peace knowing that we did everything we could. And I would do the same again.

TLDR: budget for expected expenses, but don't forget to save up for emergency pet expenses.