I'm writing pm's for a mechanism using lots of shafts and solid bushings, 2+ million cycles per year. Low speed, 25% rotational movement. Lots of load cycling on 30 second intervals. 1/4"-1" shaft dia. Dusty indoor environment. No grease fittings or continuous oiler at this time. Any ideas on frequency of bushing bearing change out on bronze bushing vs. roller bearing? Don't have good data on prior time to failure. With 8-10 hrs to change these out I'm thinking every 6 months (say at 1 M cycles) might be reasonable. Unplanned downtime is costly, $1000 per hour ave contribution of this line to company profits. Currently we wait for failure then fix.