Resetting travel limits and force settings is something a lot of owners handle fine with the manual that came with the unit, assuming you still have it. Clearing the sensor eyes of dust, checking the chain tension, and replacing a dead remote battery are all reasonable DIY jobs.
Where we'd stop you is anything involving the door's spring or cable tension, or diagnosing why an opener keeps straining against a door it may never have been sized for - on a house with original or older replacement hardware, that sizing question isn't always obvious from the garage floor. Get that wrong and you can burn out a second motor chasing a problem the first one never caused. If the opener is working harder than it should, that's worth a second pair of eyes before you spend money on a new unit.