I like the benefits of being a master in mercantile skill. It costs about 90k drakes to pay for that much training, but more than pays for itself. Do any of you do this or pay for any other training regularly?

Some of my characters pay for limited training. Typically, a fighter type will buy some armorer training, and possibly some training in a combat skill s/he is not skilled at, but needs (an example would be Marksman for a default Warrior class.) I feel that certain skills (Armorer, Marksman, Blade) can reasonably be learned and developed by working with a teacher, but that other skills (Heavy Armor as an example) make more sense as being developed through use, in the field. I realize that's probably an idiosyncratic view.

Most of my characters don't buy training. Especially with mages, where I regard the process of learning the spell as the "training," and then it's up to the student to practice. That's actually what we see them doing in the Arcane University.

I have never managed to get my mercantile up above 50 since it levels so slowly. Never thought about paying for training in mercantile, but I may consider it in the future.

Many of my characters pay for training in my vanilla games, up to the limit of 5 per level. In my modded game, I have removed the training cap but doubled the price. Since I have also reduced the amount of loot available in the world by about 70% and made merchants better hagglers with a limited amount of coin, none of my modded characters ever seem to have enough money to pay for training.

In my vanilla games, my characters have trained many different skills but their most often trained skill is armorer, which pretty much all of my characters train up to 50 as fast as possible so they can repair enchanted gear. Given the speed stuff wears out in Oblivion, the distance between dungeons and cities where repair services are available (not to mention Oblivion realms), and my personal aversion to fast travel, only my pure mages and masochists forego increasing armor to 50 as soon as reasonably possible.

Yeah, I use it mostly for skills that otherwise are really slow to practice, like mercantile or athletics.

My primary character paid for training in Restoration because she was terrible at it. She was great at the other schools but Restoration was always a drag so she needed a bit of help. Sort of like hiring a tutor.

RP justification aside, I tend to train when trying to grow my attributes "efficiently" for the first few levels when grinding a certain skill (like the Combat ones) isn't an option.

My character tends to buy some armorer training until she can repair enchanted gear.