It varies on tapas so it's hard to say, sometimes i have spurts of a lot of subs (for example if I update a lot on multiple series on the same day, people on tapas are more likely to sub to more comics by the same creator it seems, and that helps me reach out to even more people) (or if I get daily snack or something), and sometimes it remains stagnant for a few days. Maybe even sub loss, however that's rather rare.
On LINE I gain like 100-200 each update but then I also lose tons of subs there all the time haha, LINE subs are quicker to lose patience with the plot or get pissy about not getting their gay smex or whatever.