You have it the wrong way round in my opinion.
If you decide who to vote for, before any information on what they will do, you shouldnt be allowed to vote.
This idea that anybody but the incumbents is better is how we have lurched from tory incompetence, to labour incompetence and on and on. Until, as an electorate, we debate policy not (un)popularity we will continue to willing elect those in politics for entirely the wrong reasons. Blair to Johnson, the difference is minimal and history will record it as so. Lets demand better, for our kids sake if nothing else.