I understand why other people might want to get their hands on someones Horcrux, but once the bad guy/gal has split his/her soul and a piece of it has been interned into whatever vessel that was chosen to be the Horcrux, why was there a need for the person that created it to be able to retrieve it?
As far as we know, you don't physically need the Horcrux object in your possession to resurrect yourself (at-least not with the method which Voldemort and Wormtail used in Goblet of Fire).
Note: don't confuse the Diary as a physical means of re-incarnation; as I understand it, it was the 'memory' part which was doing the resurrecting (using Ginny's life-force) and not the Horcrux part1.
Why Make Them Accessible?
Let's look at it from Voldemort's point-of-view (since his is the only one we know of - Herpo's details are quite obscure and won't really help us here).
How do I know they are ok?
Voldemort needed to check-up on his Horcruxes once he found out that the trio was after them. I believe this is the primary reason to have them accessible.
Kill two birds with one stone
Some of his Horcruxes had more purpose than just tethering his soul to this world, showing his cunning by not wasting an opportunity to make use of these hard-gotten devices:
- Diary: Had his memories instilled in it which was designed to entrap and ensnare any unsuspecting readers.
- Locket: Had a powerful curse which would cause the possessor's mind to get corrupted, designed to perhaps cause dissension among his enemies (maybe even confuse someone enough to walk straight to Voldemort?)
- Nagini: Very powerful snake, able to communicate with and do Voldemort's bidding, mobile so V could keep her close at hand.
- Peverell/Gaunt Ring: Extremely powerful curse placed upon it; touch it and you die fiend!
- Quirell: Questionable (Quirell was a quasi/temporary Horcrux), but similar to Nagini, he was used to perform Voldemort's bidding.
I see you're on my Horcruxes' tail, let me just put it over here now
Another reason to be able to access your Horcruxes is to be able to move them if need be. Lets say you catch wind of someone being on your Horxruxes' tail; if you cannot access them, then you have no chance of grabbing them and moving them to another place.
Just Tell Me The Answer Already
In summary; It doesn't seem like it is essential to access your Horcruxes after you have made them, although you may see fit to check-up on them, or change their location if you see that someone is on their tail.
1. Correct me if i'm wrong; but that is what I understand from this: https://scifi.stackexchange.com/a/27492/21267
As I mentioned in my answer to this very similar question a couple minutes ago, it seems to me that a Horcrux that is accessible can be used for resurrection (like Tom Riddle's diary). As such, it is not normally retrieved by the wizard who created it, but by one of their followers (as most of Voldemort's horcruxes were).
They would need to know where it is in case they have to use it. Beside that small fact they never had to know where the Horcrux was. Also, the Horcruxes are capable of taking care of themselves to a small degree, but they also would have to make sure they have the same amount of Horcruxes and that someone didn't destroy them.
Reasons for knowing the location of your Horcruxes.
The object is important to you (Nagini). A lot of Voldemorts plan include Nagini he needed her and liked her companionship.
You want to keep tabs on the item in case someone killed one. Voldemort did this at the end of the Deathly Hallows. He searched for them and saw that they were being humted, if he had of kept tabs on them earlier then the problem would not have presented itself.
You for some reason have to use it. Possibly to reincarnate yourself, or there is a spell that you want to do with it.But I don't know how canon this is.
Someone is hunting them and you want to relocate them. Or you just want to relaocate them, in general.
Voldemort (as a example) made his Horcruxes out of rare, expensive, magical items. His Horcruxes were his wealth, backup plan and pride( no one else made 7). I think those are good reasons to know the locations. I mean everybody knows the locations of there favorite items. So in Voldemort's case I would say he knew, becasue it was vanity and he wanted to check on them. And because he had a case of paranoia.
But for all service purposes, since he left his Horcruxes alone it does not appear that they needed addtional maintenance beside being created. So that is not a reason to access them.
However, if you are asking if it is a common practice that people keep a tab on there Horcruxes then I would say possibly no and yes.
Herpo the Foul was the other holder of the Horcrux and he had 1. That means that he could have held the Horcrux as a ring on his finger or cast it into a chasm that he had put a extension charm on. But either way not much is known regarding his preferences. But we do know he died, so he obviously didn't take good enough care of his horcruxes.