G'day Mate and welcome to TBN from Downunder.
Well now, that all depends...

Did your tractor come with its Owners Manual
and was the previous owner diligent in recording the maintenance that was done over the years? The Owners Manual will tell you the various fluid capacities and the recommended fluids to use, plus the type of filters (fuel, oil & hydraulic) required.
For 'piece of mind' I'd start from scratch and change ALL the fluids (yes, even the expensive hydraulic fluid) and the respective filters.
I'd use a torque wrench (Owners Manual gives the specs) and check every bolt (especially the wheel nuts) that I can possibly see.
Grease every grease nipple (zerk) that you can find... surprise! There may be some that aren't listed.

Then I'd spray lube anything that can 'move' that doesn't have a 'zerk'. (think of pedals, linkages, etc...)
I reckon that that's enough to start, anyway. Oh, and enjoy the site. :thumbsup: