A few years ago, I read something that said some skills are slower/more difficult to decay than others. Found something on another website that had an old list of the order in which people thought skills decayed, determined after lots of tedious testing. However, the list wasn't updated with newer skills. After stumbling across that list and running into several of my own skill gain roadblocks, I posted in the UO Players forum and then also submitted some questions in the Ask the Devs section. Basara was kind enough to try to provide an answer, but I really would still like to have one of the designers/developers to provide an answer.
Here's a link to the post I made in January 2010 in the UO Players forum that includes a copy of the question I submitted to Ask the Devs:
http://vboards.stratics.com/uo-play...king-list-skills-ranked-decay-difficulty.html .
If it is actually true that some skills are more difficult to drop than others, then it may be that when you are trying to gain in a skill that decays easier than a skill you have turned down to let it decay, your gains will be slower and in some cases might even stop altogether for a while. If you find yourself in that situation, perhaps the least frustrating thing to do to get gains going again is to use an empty soulstone to flush the unwanted skills instead of just forcing them down as you gain in other skills.
Here's that old list of skills, from easiest to hardest to decay, that I found on an old UO skills training site. It is of course missing some of the "newer" skills like Bushido, Chivalry, Discordance, Focus, Imbuing, Mysticism, Necromancy, Ninjitsu, Spellweaving, Stealing, and Throwing.
Alchemy
Anatomy
Animal Lore
Item ID
Arms Lore
Parrying
Begging
Blacksmithy
Fletching
Peacemaking
Camping
Carpentry
Cartography
Cooking
Detecting Hidden
Evaluating Intelligence
Healing
Fishing
Forensic Evaluation
Herding
Hiding
Provocation
Inscription
Lockpicking
Magery
Resisting Spells
Tactics
Snooping
Musicianship
Poisoning
Archery
Spirit Speak
Tailoring
Animal Taming
Taste Identification
Tinkering
Tracking
Veterinary
Swordsmanship
Mace Fighting
Fencing
Wrestling
Lumberjacking
Mining
Meditation
Stealth
Remove Trap