Indoors Only?

Question
Hi, Labman.  

I have a 3 month old teacup poodle.  She weighs 2 pounds, 13 ounces.  Her projected weight is 4 pounds, so she will remain very small.  I am attempting to housetrain her to use a litter pan with a wee-wee pad in it.  I plan to use this method throughout her life.  Is this possible?  I have read that dogs will not adapt to going potty strictly indoors.  I have had her for 3 weeks, and she is doing a satisfactory job at remembering to go only in the potty, although some days are better than others.  She also knows that she can go potty outdoors when on a walk.

Also, at what age are most dogs completely reliable with their potty training?

Thank you for your help.

Answer
Since I lack experience with indoor relief, my answer will be speculative.  I do know some people use it.  At 3 months, I would expect a dog to be doing quite well inside.  A big factor in going outside is how careful the owner is to notice the signs the puppy needs to go or is at the door.  If it has access to the pads without your help, it should be doing very well at 3 months.