One question though. How the heck would they reduce chance of a deck fire? Don't understand that one. The reason I consider removing them is because I read somewhere, where a guy had a belt jumping off due to crap getting built up in there and pushing the belt off. I think he needed to clean it out more often to prevent that, but none the less, it caused a problem. Holding grass, dirt and debris in there around your pulley is what I don't like. That would hold moisture in there risking early rust. Also, I like the idea of it being open for ease of keeping it clean, and for constant monitoring for any issues before they become issues. Sure, safety has to be thought about even more so with exposed spinning parts, so you can't let your guard down. But, you shouldn't let your guard down regardless. I do think they are put on there, and should be put on there by the manufacture to prevent liabilities for lack of paying attention of the operator. Anytime my mower or any equipment is running, my alertness is on point (or at least it should be). Not that I have never let my guard down, but the times I have, generally ended up in something breaking, or someone getting hurt (usually me). I understand the reason for them. But I feel there is more benefit with them not on there as long as you are aware of the dangers that could arise due to not paying attention. But the fire thing, I don't get.
Well the best mowers have complete guards, not just end caps and those mowers get amazing belt life.
With the guards on debris will build up under the guard, but it packs in tight and block off any vents if fitted.
The grass under the guard tends to rot I have even seed seed germinating under a guard.
Without the guards debris sits in the air and dries out hen friction from the belt rubbing on it will make it smoulder and the draughts caused by the blades spinning till fan the smouldering grass till it catches.
The above is for people cutting wet green grass.
Down here all of the large expanses are sunburned & dry if not dead.
I have already done 2 decks that started to burn and neither of them had any belt guards fitted.
In this case the grass had just covered the entire deck and burst into flame,
The Cub has a quick release deck & the owner just dropped the deck & rode away as the burning deck started a grass fire which ended up burning about 200 acres cause the grass was very dry.
The second was a commercial mower a Toro Z Master so the deck does not quick release . The owner tried to get it some water to put the fire out, but it got the better of him.
As luck would happen all he lost was the deck fittings a lot of paint , a bit of the seat one front wheel & the wires .
He has been involved in mower fires before so had the sense to drive out backwards to keep the fire on the deck & away from the fuel tanks.
Never had a mower in with a deck fire that had all the belt guards fitted.
So it is hoses for courses, but both of them keep their mowers clean and both had removed the guards so they could blow them down with leaf blowers after each use.