For the original poster: Lock 'Picking'
All locks
Remember that locks of the same category can have a wide range of variety and quality. The lock on my bedroom door is quite easy for anyone to 'pick' with a small screwdriver or a variety of other objects while my front door would be considerably harder.
There are often many methods of getting the lock opened without having to pick it. A good con, might get someone to open the lock for you or gain you the information needed to gain access. Breaking in via an alternate method (bust out the door jamb, break a window, use an air vent, ) is common.
Key locks
IMO, picking 'old fashioned' (depending on tech level) mechanical locks would be quite rare so not having a specific skill for it is not an issue. Even where these types of locks are common, picking them typically is not. Cutting or other wise breaking the lock is popular.
When lock picking does occur, how about using Dex with bonuses for appropriate tools and don't forget that Athletics (co-ordination) DM? After all, Athletics (co-ordination) is one of the skills under Thief.
Combination Locks
Similar to key locks, these locks are often easy to break or bypass.
We could have another conversation on safe cracking. A safe could have a lock other than a mechanical combination lock. To me, a safe is just a more solid and secure container which makes breaking in via an alternate method much more difficult. Typically a safe has a more secure version of whatever style of lock is used.
With combination locks you have the opportunity to try to use, intelligence (try a birth date, phone number, ...) , deception (hide and watch them open it), stealth (plant a hidden camera), and many other possibilities.
Biometric locks
retina scans, fingerprints, voice recognition, DNA
Yes, some electronics or computer skill can maybe let someone activate (unlock) this device. You could record the persons voice. You could chop off their hand or head. Don't forget all those previously mentioned alternate methods.
Electronic locks
magnetic cards, pass code entry, encrypted EM signals (simple example is the remote for opening a car door)
Same as biometric locks, some electronics or computer skill might let someone 'hack' this device or a central computer that controls it. Stealing the card or signal generator is an option. Pass code locks are susceptible to some of the same methods as combination locks.
For biometric locks and electronic locks, having specialized equipment would give a much better chance. Without it, using just electronic or computer skills might be impossible depending on the quality of the device.
Additional note. Since skills can be broad, I usually take a characters background into consideration when determining the task difficulty. A Rogue thief with Dex 9 and Athletics(coordination) 2 skill would be more likely to pick a lock than an Entertainer performer with Dex 9 and Athletics(coordination) 2.
