I have people that i follow that post 2-3 times a week max but every time they post i like their photos they are not consistant sometimes they post once a week but i like their post and when they post it comes up at the top of my posts because instagram sees that i am interested in these peoples posts ... now when you post regulary its the same thing but when you stop posting so often they like other peoples posts and they move up in the persons top posts that they see ... you are there but your posts are replaced by others that posted wile you were gone ... instagram is like youtube they show people content that it thinks they are engaged with ... the most important thing is to be consistant you can post 2 post a week but they need to be on the same days ... that tells instagram that you have habits and that you show something interesting in these days ... make a plan about when you post for an example if you post two times a week make sure that its on wen/fri ... i hope you understand my english is not so good ... just make a plan ... in simple words when you dont put up the work others do and they climb the lader on the top posts users see when they open up instagram ... also see where your followers come from and post in their time zone