My rule of thumb is that Thief’s skills come up when it’s an automatic failure for anyone else: anyone can try to disarm a trap by telling me what they’re doing, only a Thief can make a roll to fidget around its mechanism to disarm it with no clear plan. Lockpicking becomes more problematic here, but my rule of thumb is that anyone can force a door open by damaging the door and/or the lock, while only a Thief can properly pick the lock (and thus ensure no traces are left and the door can be locked again if needed).
I also tend to adapt the descriptions to the characters: spellcasters get more details on weird runes/symbols, Fighters more martial stuff and Thieves a bit more hints at hidden things (for which they still have to search). This way variety in the party is a bit rewarded and every character has a bit of room to do their thing.
Since I like rolling with 0e the Thief is really the person who I look to be excelling out of combat and in exploration. It takes a thief to muck around with a non-descript trap to disarm it or to climb up a wall without a purchase to throw a grapple hook to. Lock picking and hiding in plain sight are domains of that master. When you want to get a drop on the monster or need to focus on utility over damage, then that’s the thief.
Everyone has the ability to avoid or trigger a trap in a controlled manner, you won’t know if it’ll stay inert or for how long, a thief can make sure it stays safe until it’s messed with. Anyone can knock down it force a door but that’s loud. Anyone can press their ear to a door but only a thief can tell the difference between breath and a draft. A fighter is usually going to stay up front and stay with equipment to fight, a cleric needs to be ready to repel dead or support where needed, a mage needs to be ready to dish out damage or control the field, the thief is there to make sure that the odds are still in everyone’s favor when the dungeon doesn’t want it to be.
Having played with absolute newbies to ttrpgs in general (one shots at cons, mostly), I’ve seen that telling them they can’t even attempt to lockpick is a turn off. So this is my ‘hack’ for this.
Remove the thief.
Give everyone thief abilities.
And under the hood it works something like this:
All characters can attempt lockpicking, finding/disarming traps, pickpocketing, moving silently, hiding (in shadows), climbing (sheer surfaces), listening (doors), and reading (languages), as long as it is reasonable. For instance, if they have thought of bringing a set lockpicking tools, the players should at least be able to attempt the task. Or, if they remove the chainmail they’ve donned so that they want to move silently, they should also be able to attempt, etc. So, common sense would be the guide.
Then, the referee assigns a difficulty to the task. Average (4+), Difficult (5+), Very Difficult (6+). The attempting player rolls a d6 and adds the related ability modifier to the roll. If the sum is equal or higher than the difficulty value, it’s a success.
Skulduggery Related Ability Score
Lockpicking DEX
Finding/Disarming traps WIS
Pickpocketing CHA
Moving (silently) DEX
Hiding (in shadows) DEX
Climbing (sheer surfaces) STR
Listening (doors) WIS
Reading (languages) INT
Mages receive a +1 bonus for reading and disarming (magical) trap attempts.
Clerics receive all WIS-based attempts +1 at temples/graveyards.
I haven’t played it myself yet but I really like the specialist class from Lamentations. It feels easily malleable with the unified skill list and has a strong identity as “this is the class where you pick the advancement” when it’s the only one in your game that does this.
It doesn’t intrude on the other classes and it’s been a hit with two of my players so far (one going for a classic thief character and one going for something like a sage).
I like to use the Turn Undead Table for resolving Thief Abilities when there are stakes and imperfect conditions. I prefer it to the binary resolution methods because it uses that triangular distribution, allows for partials, and can set the Difficulty for me in most instances.
In terms of the various abilities themselves, if a Player finds the standard ones lacking, there’s always my d4 Caltrops: d100 Unusual Thief Ablities table to provide more ideas.
0e fucker here, I just use a universal x-in-6 mechanic for all “skill rolls”, modded off a friend. 2-in for difficult, 3-in for normal/average, and 4-in for easy, with situational or mechanical +/-1’s. I adapt stuff like the racial listening bonuses and such as affecting the base chance with some fiat. Everyone can be a thief.
Grabbing these from my players guide (work in progress rn), but there’s a couple additions from the RC Errata document and Threshold mag (alongside the codification of the Rake class from DDA1 - Arena of Thyatis). The primary changes are as such:
Use of any One-handed weapon
Use of all missile weapons
Use of Staves/Quarterstaves
Ability to use magic scrolls at 1st Level with 25% chance to fail/backfire (Improved to 10% chance at 10th level)
Backstab can be done with any melee weapon (such as a club), gets +4 to hit, and after rolling weapon damage the thief can choose to take 2X their roll or negate it and instead take the highest possible damage for weapon (any modifiers are then added)
Can forgo improvement of Spellscroll use to learn Snipe which functions as a ranged Backstab up to 30’/90’ (dungeon/overworld)
All Thieving Skills receive a Bonus or Penalty of 5% for their ability modifiers with the applicable modifier depending on the skill.
For example, a Thief with 13 DEX will gain a +5% (5% x a DEX modifier of +1) bonus to their attempt to use Move Silently to sneak up on a sleeping orc, but the same Thief has only 5 INT and will incur a penalty of -10% (5% x an INT modifier of -2) when trying to search the next room with Find Traps.
Until 4th Level, the Thief is able to reroll abysmal failures for any application of their Thieving Skills. At 1st Level this is considered a roll that is ≥ 91, At 2nd Level this is a roll that is ≥ 96, and at 3rd Level this is only on a roll of 100/00.
The Ability Scores that govern Thieving Skills are as follows
Open Locks: INT Find Traps: INT Remove Traps: INT Climb Walls: DEX Move Silently: DEX Hide In Shadows: DEX Pick Pockets: DEX Hear Noise: WIS
Oh for what thieves I use, I’m kinda always up in the air. I often prefer to play without thieves, but my players generally don’t. Even when I’m like “just be a fighter, you’ll have better to-hits, you just wear leather armor, sneak around, and buy tools” they’re like “if I’m gonna do that I want to have a name tag that says ‘thief.’”
So I just port in whatever version, often the FMAG version (which for historical note, the notion of using “hear noise” as a universal thieves skill system to get around the annoying percentages predates FMAG and the OSR generally).
For my current open table I’m using them straight out of Greyhawk.
A way to resolve that kinda is to have “character kits” of sorts. Turning the standard thief abilities into general skills like those in BECMI (which do have some overlap in the RC!) and then telling players “hey if you take all these in lieu of other skill choices, your character is now a Thief” and gets some of the bonus abilities from the thief class.
Makes sense from a fantasy point of view. Churches would definitely employ members who could do more covert missions or get critical artifacts, mages who focus more on “practical” means of rooting around for dusty tomes and decide to pick up tricks that help with their methods, fighters who take up bounty hunting jobs and need an extra set of skills to assist…