Mr. Ollivander anteckningar har några intressanta saker att säga på detta ... men först, kom ihåg:

The best wands, he believed, had cores of immensely powerful magical substances, which were expertly enclosed in specially selected and complementary wandwoods, the result to be matched to an owner with whom the wand itself felt the most affinity.

...

His methods of locating wand woods and core substances marrying them together and matching them to ideal owners are all jealously guarded secrets that were coveted by rival wandmakers.

(Mr. Ollivander on Pottermore by JK Rowling)

Every single wand is unique and will depend for its character on the particular tree and magical creature from which it derives its materials. Moreover, each wand, from the moment it finds its ideal owner, will begin to learn from and teach its human partner.

...

The following notes on various wand woods should be regarded very much as a starting point, for this is the study of a lifetime, and I continue to learn with every wand I make and match.

(Wand Woods on Pottermore by JK Rowling)

Readers should bear in mind that each wand is the composite of its wood, its core and the experience and nature of its owner; that tendencies of each may counterbalance or outweigh the other; so this can only be a very general overview of an immensely complex subject.

(Wand Cores on Pottermore by JK Rowling)

However, no single aspect of wand composition should be considered in isolation of all the others, and the type of wood, the core and the flexibility may either counterbalance or enhance the attributes of the wand’s length.

...

Wand flexibility or rigidity denotes the degree of adaptability and willingness to change possessed by the wand-and-owner pair - although, again, this factor ought not to be considered separately from the wand wood, core and length, nor of the owner’s life experience and style of magic, all of which will combine to make the wand in question unique.

(Wand Lengths & Flexibility on Pottermore by JK Rowling)

TL; DR För att sammanfatta, medan en trollkarl kan ersätta sin trollstav (som vi ser Charlie Weasley gör) kommer de inte att "ut växa" den. Varje stavägare har ett mycket unikt instrument och staven lär sig och växer med trollkarlen.

I de allra flesta fall växer muren med guiden.

När en trollkarl först får sin troll, när de använder den, lär sig sin trollstav och växer med dem. För de flesta trollkarlar betyder det att deras trollstav blir mer, inte mindre, lämpad för dem när de växer.

“The best results, however, must always come where there is the strongest affinity between wizard and wand. These connections are complex. An initial attraction, and then a mutual quest for experience, the wand learning from the wizard, the wizard from the wand.”
- Harry Potter and the Deathly Hallows, Chapter 24 (The Wandmaker)

Även om det inte finns några instanser vi vet om var en trollkarl ändrats så drastiskt och snabbt att de växer ut på trollet, kan det vara teoretiskt möjligt och om det skulle hända (kanske orsakat av en händelse som helt förändrar dem), förmodligen trollkarlen skulle bara köpa en ny trollstav.