I treat my airboat like an aircraft! It’s inspected before, during and after use EVERY time. Oil and filter changed at a maximum every 45-50 hrs, coolant is changed bi annually or at least annually regardless of extended life coolant. Every oil change I go over every bolt and insure it is snug or retorqued, all bolts on engine, fuel rails, alt.bolts everything! Use top quality oil and filter, I run a mobile 1 301 or Royal purple filter out of all test they are top. I have buddy that does oil filter swap at approximately 50 hrs and does oil only every 100 hrs, no issues with is motors at all either. Keeping you operating temps down to 170ish will increase longevity ten fold. On my rig a lot of folks I’ve talked with say I go a little over board on maintenance and inspection however it’s not me I’m worrying about it’s someone else getting hurt because I didn’t do something or could have prevented it. I do walk around constantly looking for anything loose or cracked. I change fuel/water separator filter and fuel cell filters once a year. I have a schedule or routine I don’t stay from so I don’t get complacent and forget to check something. This is just how I do it I am sure I have forgot a few things I check and I’m sure others will chime in on what they do or don’t do to keep running without wearing out an engine.