Hello, i have a question. I have installed a physical copy of The Sims 3, i updated it to version 1.67.2 with the superpatch. The question is: I have both High-End Loft Stuff and Late Night expansion packs, but they are on v3.0.38 and v6.0.81 when the latest version of those EPs are v3.13.1 and v6.5.1. I found the installers in this page, but are they neccesary?

According to the official instructions by EA it is not necessary to update EPs.

Some people here, however, advise to still do it.

I didn't and I haven't encountered any problems, but I don't know whether updating the EPs separately makes any difference. The old patches are still here because in the past it was indeed necessary to update them individually but EA changed the patching process sometime around Generations and now all updates go into the base game and affect all EPs. So, people who play with older patch versions may still need the EP patches. But you don't if you are on 1.67.

I'm on base game v1.67.2 but on Late Night v6.0.81, while the latest is v6.5.1. Late Night was released before Generations, so, i need to update it, right?

No, the EP version doesn't matter anymore. For Generations EA changed how the game runs. Before that you had to launch your game from the last EP but this was replaced by ts3w.exe, which is the "new" base game that contains all EP stuff and the EP exes are now redundant. All patches since then (and that includes 1.67) only patch ts3w.exe. (That's also why they are so big now). You can patch the EP but I think that it doesn't have any effect because the engine reads ts3w.exe anyway and doesn't look into whatever an EP patch did to the EP data.

Yes, you are right. I updated the packs to their respective versions (3.13.1 and 6.5.1) but i didn't see any change. And while the patches were installing the patched file was TS3.exe and not TS3W.exe, so, yes, it's not needed. Thanks for answering!