Curious on how often you would need to add hydraulic fluid between hydraulic fluid changes. I know about the window that shows how full. Based on the appearance of that window when do you normally add some? New tractor owner and have 13 hours on it. It appears I can’t see fluid in that window. I did have a some leak out when I was trying to attach my grapple but it seems that would have been enough to drop level outside window. What do you think?