I try to take quarterly profits when any fund I own has gained 10%...more often than not I wait a lot longer then 3 months, but by doing a review quarterly I usually avoid early redemption fees and I find that there is at least a few holdings that have performed well enough to sell some shares.
If the holding is an opportunistic position and it shows signs of upward momentum I usually will only take the 10% gain and monitor its momentum more closely. I like to use a pairing system with my mutual funds.
Recently, I have been pairing BUFBX and BUFOX. In this case I use BUFBX as my long term hold and BUFOX as my opportunistic position. Here are the two funds over the last quarter:

In this case I will take my 20% gain from BUFOX (referenced against BUFBX) and reallocate it to BUFBX. I will check momentum of BUFOX against BUFBX on a 1 month basis going forward. Here's the most recent 1 month chart:

As you can see, BUFOX continues to have positive momentum compared to BUFBX. If things reverse I will often get out of the agressive position and continue monitoring it for reentry or look for other trending funds.
I have tried this also with:
Mathews Funds: MAPIX and MSMLX
TR Price: PRWCX and many other T R Price Funds (PRMTX, PRHSX, PRIDX, PRNHX, etc)
Vanguard: VWELX and other Vanguard Funds (VHCOX,
VGHCX, VGENX,VGSIX,etc.)
Pimco: PONDX and other Pimco Funds (PCKDX, PETDX, PCRDX, etc.)
Oakmark: OAKBX and other Oakmark Funds ( OAKIX, OAKWX, etc.)
I try to do these investment pairing within the same fund family because my brokerage allow me to exchange funds on the same day. This provides me with the ability to sell profits from my opportunistic funds and buy shares of my "long term hold" fund on the same day. Choosing funds that are NTF also eliminates transaction fees.
Would like to hear from others on their reallocation strategies.