No Partial Boosts

[Ravingdork]

At the levels in which you get ability increases, I allow my players to reset their attribute modifiers so that at each interval of 5 levels, they always have the best stats, with no "useless floaters." They can't have +4 Strength and +0 Intelligence at level 1, then swap to +0 Strength and +4 Intelligence at level 5, but I do let them tweak the numbers a bit so that there's no useless floater to worry about at any level. I think it's a pretty good house rule that prevents a lot of "feels bad" moments of character building and remains balanced since it always falls within the bounds of normal character builds.

What are some potential unseen ramifications of such a house rule?

[A Butter Idea]

It sounds like you're looking for a way to make players feel like their attributes are continuously improving. Why not instead try my revised Gradual Attribute Boosts house-rule: https://scribe.pf2.tools/v/ws9MLyWC-gradual-attribute-boosts

Cliffs notes: Players get to improve an attribute every level. They don't need to track which attributes they've improved recently, and can improve the same attribute on successive levels. The only limitation is that attribute values are capped based on player level. It's all balanced to be in-line with the RAW power progression.

In my system, you still have partial boosts, but unless the player is deliberately making weird choices, a player will only ever have one partial boost at a time, and the partial boost will only stick around for a single level.

[WatersLethe]

Ravingdork's house rule is kiiind of the default for one shots, short term high level campaigns, and a lot of monster of the week style games. If you're making a character for such a game, why would you waste a bonus you won't capitalize on, especially when you know you're guaranteed flexibility for character tweaks if it does come up?

I don't think it has any unseen ramifications, because it's already effectively used a lot and no one has really complained.

It's a bit of a power user house rule, but by the time it comes up new players should have enough experience to be able to handle it.

The only downside is it slightly reduces long term character narrative consistency, but so much else changes over 5 levels it's only noticeable if you're a bit of a nitpick.