Recently Google has made new updates of mobile friendly algorithms. I can see many ups and downs in the ranking of my website. Although some of my websites are mobile friendly and some are not. Still can't find the solution how it affects the searches in the Google ranking. And also want to ask it is important to make our website more mobile friendly and responsive as it get me to pay extra amount of time and money.

I think every site can benefit from mobile capability. Even if you determine your site isn't being visited that much by mobile devices, it could be that people aren't sharing links to it because it isn't mobile friendly.