Basics on Time Machine aren't clear.

If you delete files they will still be on time machine just not on the more recent backups. What I mean is if you open up the time machine program and look back at say july 9th ( and assume you deleted the file today ) it would still be there on the july 9th backup and the older ones but if you looked up july 12th ( after you deleted it ) it would not be on that particular backup. Time machine keeps backups of all your files as they were on the day. Usually you can look back months and months on your time machine if you need to.

In other words don't worry about it, time machine will manage everything.

 

Keep in mind that if you fill up your backup drive, then it will start removing older backups to free up space, so if you don’t want to risk losing files you’ve deleted from your computer from the Time Machine backups, then just make sure you’ve got a drive that’s plenty big enough. 1.5x to 2x the size of your internal hard drive is a good rule of thumb for a backup drive, but if you only use 50GB of your drive space, a 500GB backup drive is probably overkill. They’re cheap enough now though, that it’s not usually too expensive to just get the biggest drive you can reasonably find.

jW