I've broken 3 locking blocks in my PT92 and most of the time you can get the Pistol field stripped to get it out, but not always. My second Locking Block required Taurus to cut out the Barrel out to get my PT92 apart. Taurus put a new Barrel and Locking Block in and everything was fine, for awhile. In my experience, PT92/99 Locking Blocks have a 5000 to 7000 round life expectancy with Standard Ball Ammunition and Recoil Springs. I have some 22,000 rounds thru my PT92 with more coming.
In general, Beretta has recommended replacement of the standard M9 Locking Blocks at 5000 rounds. M9 Recoil Springs must be replaced at about 15,000 round intervals, or when needed. Trouble is, such maintenance is not always done, and this has been a problem with other small arms throughout the history of the U.S. Military. Also, some penny pincher at the D.O.D. decided to purchase poorly made aftermarket spare magazines for the M9, made by unskilled peasants in South Africa. These problems have caused some knee jerk condemnation of the M9, most notably by 1911 fancier/armchair Generals, who have no memory of the rattle trap 1911's often issued during the Vietnam conflict, which very often did not work very well! But this is no good reason to condem 1911's either. Properly maintained, either will serve well!
Beretta has recently upgraded the materials of the Locking Block and modified it's Design to avoid breakage of the locking wings. The new Beretta Locking Blocks have been tested to withstand hard use of 40,000 to 50,000 rounds. Also, in addition to the new Locking Block, the new Beretta 902, has a two stage tandem recoil spring system.
On a historical note, when Massimo Beretta was copying/adapting/simplifying the Walther P38 oscillating wedge locking system into the Beretta 950/951 and later 92 style pistols, he did not get things quite as well done as they were on the Walther. P38 locking blocks almost never break, and generally last the life of the pistol.
My PT92 currently has one of the newer Beretta Locking Blocks in it, as well as a higher power 15 pound Wolff Recoil Spring. The standard Beretta/Taurus 92 recoil Spring is rated at 13 pounds. Wolff has done studies of recoil springs for various 9mm pistols and found them to be undersprung.
Unfortunately, the vendor I purchased my Beretta Locking Block is no longer in business, so I cannot tell you where to get one, but if someone else knows, please, by all means, chime in!
Beretta now has a third Generation Locking Block available, which is technically a fourth, as there were two versions of the second. However, it is the latest one available and I found one vendor selling an update kit:
Taurus will send you a free new locking block, provided you send them the broken one, but purchasing a spare to have on hand, should breakage occur, might be a good idea. I recommend getting a new style Beretta Locking Block and a 15 pound Wolff Recoil Spring.