[IL] How long does a bad work history have to be improved to be considered where you work?

I'm not sure if this is the right place to ask, so please let me know elsewhere if there's a better place!

I have had health problems previously, and for 2-3 years, I was working 6 months here, 6 months there, but never longer than 6 months. My attendance was trash because I was in the hospital a lot. I took a year off. I've been working on my health, and I have perfect attendance here at my current job. In my last job, I worked 11 months and missed 2 days. My current job, I'm about to hit 3 months, and I've never missed a day and I cover others shfits. I'm trying to figure out how long I should work here [or how many long employments] before I am *more* appealing to HR/Employers. I am trying to get to 18 months bare minimum at this job. I know this likely depends on the company, how desperate they are, the applicant pool, etc. The jobs I really wanted always turned me down, so I'm trying to fix my work history so maybe I can land a better-paying job. Any input?