good point about measuring the temps with an IR 'gun'
One tip though, from an old reliability engineer...
measuring and getting the numbers is good, but at the same time I think its good to still lay your hand on the things to develop a 'feel for it' about what it should be like. you won't be able to notice very small trends, but you never know when your batteries might be dead.... general rule of thumb is that if you can lay your hand on it and hold it there things are ok...(although I suppose the brake thing you pointed out really skews that)
Anyway, we used to do that all the time when we were doing vibration analysis. With that high tech tool, micro vibrations could be detected and you could differentiate between a future outer race failure, inner race failure, roller failure, cage failure...often even before you could find any defect at all visually on the bearing using a magnifying glass...
but even with that tool we would lay our hand on it and often do the old "broom handle" trick to listen to the bearing. we could then compare the old school indications to the high tech indications and we learned to often hear or feel things just walking by without any fancy equipment at all.