I'm a long time player that just came back to UO after being away for several years. Super excited about all the new pet training options but having a hard time figuring it out. I have some pets that I've had for years so are still the old control slots. I was working on my 3-slot dragon and when I made him 4-slot I wanted him to have more spells so I gave him mysticism and then he lost his magery!?! Is it only possible to have one school of magic per pet? When you have them learn a new school of magic do they always lose their current ones? I gave him magery mastery and he got magery back and he has mysticism at 20 but he doesn't every cast or gain with it? Did I screw him up? Aside from pets that can learn necromage is it only possible to have one school of magic on them? I wanted to have a pet that can use magery, mysticism, and spellweaving. Is that not possible?
Read. Please Read. (that is to all returning tamers)
When you select another magic you get a warning message about the animal losing all other magical abilities it has. I have no idea why so many tamers miss this.
Most important piece of advice I can give any returning tamer, keep your old legacy pets in the stables until you get a firm, and i mean firm, grasp of animal training. Train newly tamed animals and see what abilities/magical combos work well with your play style, then revisit the legacy pets. They cannot be replaced. They cannot unlearn what they have learned. Properly trained they can be some of the best pets around. Improperly trained they will probably end up back in the stable while more effective pets are used.
Second piece of advice, be wary of any one in game giving advice. Some great tamers out there, but when I see a tamer with a 30 stam regen, 700 int, 600 str naja giving taming advice... And his first piece of advice to the returning tamer was "add hp" to his 800hp naja with 200 str.... And this guy said he was knowledgeable about animal taming...
Test Center is a good option, but some things shine with the more skill an animal has.