Can you spend half of a skill point?

[Particle_Man]

If you take your first two levels in a 3.5 class for which skills A and B are cross class skills, you can max them out by spending 10 skill points to bring each to 2.5 ranks. If you then take your third level in a class for which those two skills are class skills, and after buying up other skills have one skill point left to spend, could you split that skill point into two halves in order to increase skills A and B from 2.5 ranks to 3 ranks? Or is one skill point indivisible?

[Mr Adventurer]

Sadly AIUI skill points are indivisible, while skill ranks are not.

[NerdHut]

I'm not aware of any rule specifically calling this out. It may be up to DM discretion. Personally, I'd allow it.

In any case, it may be more worth your time (and skill points) to avoid cross-class skills unless you really need them. If you know ahead of time what levels you'll be taking, you can probably plan something out to more judiciously spend your skill points.

[Segev]

As a DM, I'd probably allow it, but by the RAW, you cannot. By the RAW, you can achieve the same effect by putting the two skill points you put into them to get them each to 2.5 into another skill that you otherwise planned to raise the next level. This will save you at least one more skill point next level, leaving you with 2, instead of 1, and the ability to buy up from 2 to 3 in each now that they're class skills.

[Telonius]

AFB, but there's probably something in the Retraining mechanic that would get you the same effect.