Timing Belt Cover
 

Is it bad if you dont have the upper timing belt cover, lets say for a f23a1 engine (6th generation accord)? I don't have one on so I dunno whether its worth going out and buying one.

no its not bad, in fact a lot of people remove them especially if they cam aftermarket cam gears, so its not bad

The sole purpose to obviously keep degris out from the timing and its gears. Also be warned that if you happen to work on your car again and a bolt/nut or whichever falls down you best be taking the lower cover off to retreive it. It has its purpose but at the same time it can do without.

I'm on the same boat my friend, lazy is my middle name.
I'll get on it one day... Unless your running a powerfull setup that needs constant attention then there is no point in putting your motor in danger.

interference engine with exposed timing belt/gears = no no.

You are just asking for a rock/some sort of debris to snap that belt.
bye bye engine.

you dont need it but u should have it just incase something falls in the timing belt area just go pick one up at the junkyard there cheap