Ability score check

[The World Shaper]

hi! i just have a few questions

can you take a 20 on say a strength check? had someone trying to break a door down he decided the best course of action would be to take a 20 until he got finally broke it down (i know that taking a 20 means you fail but didn't see a issue i mean its realistic kick a door over and over till it breaks right?)

had someone say thats low allowed just want to make sure.

Second question if you roll that naturally is a natural 20 a auto success mostly asking cause now im thinking its like a 65 break dc to break through a stone wall and mr mcwizard rolls a 20 on a str check said wall is now broken i don't see the logic there they still need to be able to make the str dc right?

[dragonhunterq]

Second thing first, skill checks and ability checks are not subject to the auto fail/auto succeed rule. That rule only applies to attacks and saving throws.

Second, you can take 20 as long as a) you are allowed to retry that skill and b) you take any penalties for the many times you are assumed to have failed.
I'd probably assign penalties based on the number you could succeed on (if you need a 15+, that's 14 x penalties), but I can see little room for arguing against an assumed 19 x failure rate.

PRD wrote:

Since taking 20 assumes that your character will fail many times before succeeding, your character would automatically incur any penalties for failure before he or she could complete the task (hence why it is generally not allowed with skills that carry such penalties). Common "take 20" skills include Disable Device (when used to open locks), Escape Artist, and Perception (when attempting to find traps).

[DM_Blake]

To build on and clarify what dragonhuntereq said:

You are assumed to "auto-fail" on a natural 1 with attack rolls and saving throws only, and you "auto-succeed" with a natural 20 only on the same rolls. This does not apply to ability score checks.

Also:

SRD, Skills, Take-10 and Take-20 wrote:

The normal take 10 and take 20 rules apply for ability checks. Neither rule applies to concentration checks or caster level checks.

So you are allowed to use Take-10 and Take-20 rules on STR checks to break down the door unless there is a penalty for failure (like if the door is over a pit and failing to break it means falling in the pit). Just bashing the door and it doesn't open has no real penalty, so keep trying until you get it right. Take-20 is perfect for this.

Side note: it's probably very noisy. Don't expect to catch any nearby monsters napping...

[ryric]

You can indeed take 20 on any ability check that you could repeat over and over with no penalty except time wasted. And you identified the issue with autosuccess and autofailure on such checks - it leads to ludicrous situations like 8 strength guys busting down walls.