I have a junky Troxel Spirit as well. It fits my head and doesn't cost me an arm and a leg.
Last month, my Paint slam dunked me and grazed the top of my head with his hoof. Some people told me to replace the helmet and some said as long as the inner foam wasn't damaged it would be alright.
I checked it over really well and it is fine. Now that I can finally get up and ride again, I used it when I did the other day.
BTW, I too am in MI.
"When you're young and you fall off a horse, you may break something. When you're my age, you splatter." -- Roy Rogers