A lot of it depends on how you use it. If you trailer in freshwater, there will be less issues and repairs. If you moor or slip it in salt water like I do, you will have to do more or you will pay for your lazyness.
Don't just depend on what people on the internet (some of whom do not know very much) say.
Depend on what the maker of the power package said in their maintenance manual. Its all in there. The problem is people like to look for shortcuts and then find bad advice on the 'net that makes them think its OK. Same thing with winterizing short cuts.
Get the manual and look at what it says. Most will say there are a list of things that are supposed to be done every year. And some more things than an outboard, but keep in mind an old school Chevy based engine in an I/O is far simpler and cheaper to repair/replace than the power head in a modern 4 stroke or DI 2 stroke outboard.
as in the following:
Change engine oil and filter
Change drive oil
Remove drive, check bellows for water, check gimble bearing for smooth operation, check ujoints for roughness/rust, check driveshaft splines/coupler splines for wear.
If grease-able, grease ujoints, gimble and grease the driveshaft splines.
Check engine alignment
Replace raw water impeller every other year.
Yearly tune up
Change fuel filter

Salt water use: remove risers every 3-5 years to check for clogging and corrosion, plan on changing manifolds/risers 5-7 years.

The outboard, does not need the drive service listed above except for the gear oil change and changing the impeller (Lower unit comes off for that). But if you never or seldom remove it they can get stuck on there good like and outdrive.

So yes the OB will need less work and this is amplified in salt water use. But the OB has other advantages, such as much easier winterizing, no worry about explosive fumes in the engine compartment, and the fact that a failed cooling hose will not fill the bilge with salt water faster than you can say Oh Sh!t. However they cost more for certain repairs. You have to choose what is most important to you.....

Wow Thanks everyone. I still have my 05 deck boat with a 115 on it. Taking family out on the 210H this weekend to decide which one to keep. We are mostly fresh water, salt once maybe twice a year.

Thanks again