I was greasing the front suspension on my 2004 FX4 II and noticed that there is a small hole in the rubber boot on the driver's side upper control arm and the grease was coming out. I checked the other side and it looks like a previous owner replaced the upper control arm on that side and there isn't even a grease fitting on the top. The boot on that side looks good though.

Is it a problem if the boot is leaking a bit on the driver's side? Is it worth the trouble to replace it?

 

I'd just keep greasing it until it starts to get loose. I've got one joint yet that is doing that...no reason to replace it until it is broken.