Dropping out of a process late in the game?

Hey all, 

I'm an experienced PE associate recruiting for new roles. As I tease out whether a certain opportunity is the right fit, my approach in interviews to date has been to stay open and accept invitations to initial/subsequent conversations or case studies to gather more information. However, in some of these processes I am now getting to a more advanced stage and am having to prove my interest level more earnestly. I am cautious of getting to an offer stage (or near-offer) and then bowing out of the process on account of some excuse like "I reflected more and this isn't the right fit", as it seems like doing this might burn the recruiters and/or the hiring teams given they'll likely feel I wasted their time. 

I'm curious about what strategies others use to manage interview processes where you aren't 100% sold on the role. Specifically, I care about how to create competitive tension in a genuine way that doesn't undermine your own integrity and won't burn bridges with recruiters / hiring managers later on.