Tire Prep and Tire Prep Machines?

Got a couple of questions. I'm debating buying a tire prep machine. I'm pretty much by myself so tire prep after work can pretty much take up all my time Monday-Wednesday and then put the car, tools, equipment, etc in the trailer on Thursday then race Friday Saturday, clean up on Sunday then repeat. So here's my questions:

1) What's everyone's thoughts on the machine from Keyser and the new machine I see out there from Love Tap Fab called Tire Demon. I can not find any reviews or youtube videos of these things in action on a late model. For $2000 loaded basically I'd kinda like to go off something other than Keyser's sales pitch at PRI

2) Why does every machine pretty much make you buy a needler. I've raced 10+ years and haven't even seen someone needle a tire. What am I missing?

3) At what point do you consider a tire junk (UMP LM tires mainly)? I'm not buy new tires every night guy. Is there a way to go off of durometer or Thread depth and know when its garbage? Yes I realize there's other factors that may be involved buy I'm wondering if there is a "yes its junk" way of knowing its actually junk.

So that being said. I don't want to make my own machine. I want to be able to get tires prep'd faster so I can do other things like work on the chassis and what not. Since I'm by myself I need Work smarter not harder if you know what I mean.

I know nothing about either as I don't have a tire prep machine, but am in the same boat as you (the one and only). What I wanted to add is that based on your asking about UMP tires, just be mindful that it looks like they're headed towards a no cut/no sipe rule, at least based on the incremental changes posted for this year (RR to start). Your money may be better spent somewhere else.

So does anyone want to help me out with At what point do you consider a tire junk (UMP LM tires mainly)? I'm not buy new tires every night guy. Is there a way to go off of durometer or Thread depth and know when its garbage? Yes I realize there's other factors that may be involved buy I'm wondering if there is a "yes its junk" way of knowing its actually junk.

There are so many variables I don't think anybody can give you a solid answer.I'm starting a log book for each tire this year because we race on wrs-2 and lm40 and will use them for several races.For the most part I sipe the tire half depth and when the sipes are worn off I go to a new tire.Any time a tire sees a lot of heat I remove it.i have practiced with well used tires,Swaped to new tires that had never been ground but siped and the car was slower for the first 2 or 3 laps