Adventurer's Skill Knack (3.5e Variant Rule)

These rules are part of the Tome of Prowess, but you don't need to use anything in that work to make use of the retraining rules presented here.

Adventurer's Skill Knack
If you had been adventuring for a while, you would pick up and remember all sorts of useful things. Unfortunately, the skill system is really bad about representing this. You can never make checks to see if you recall anything about a creature type you've faced dozens of times before, you can never try your hand at opening a lock like you've seen your companions do, and you never improve even a little bit at the untrained things that you could attempt if you wanted. To rectify this, characters gain the option to spend additional time on an otherwise untrained, or under-trained, skill check in exchange for temporary ranks in the skill.

You may use a skill as if you had a number of ranks in it based on your level, as indicated in the table below, but you must spend 4 times as long as the normal action required for the skill check. If the action would normally be performed as a free action, you must spend a standard action on it instead. If it would be performed as a swift or immediate action, you must spend a full-round action on it instead.

You may not take 10 or 15 on this skill check, even if you would normally be able to if you had invested in the skill. This is because you lack sufficient practice with the skill and are making a best guess based on things you have seen in your journeys or been told by companions. You may take 20 if circumstances would normally permit you to do so, but it takes 80 times as long as the normal action required for the skill check. In this case, you are simply 'winging it' over and over and over again until you get your 20. You otherwise act as if you had the ranks in the skill for the purposes of the check. Note that you may not gain temporary ranks in any skill that does not require a skill check, like Speak Language.