It is critical (pun intended) that you have a criticality ranking for your equipment. This will help you properly direct maintenance and reliability efforts. It is difficult to have granularity
Priority something that is more important than other things and needs to be done or dealt with first criticality a relative ranking of equipment based on the probability of its failure and the consequences of the failure.
One Monday morning, I arrived at the daily production meeting and joined a tense discussion about the three-stage, recycle compressor that had failed over the weekend. It had been a fairly reliable machine, but it was going to result in a lot of downtime while we repaired it. Being a worldscale polymer production facility, this translated to a couple of million dollars of lost economic opportunity. It was going to be a long week, but at least we had all the parts.