At What Point Should I Split or Partition a Very Large but Simple Table

Our site has some large but simple (INT, INT, DATE) tables for stats. Each table has up to 300,000,000 rows, and gets bigger every day.

The hosting provider has suggested that we split or partition the tables, and I have seen this recommendation elsewhere on numerous occasions.

However...

I am struggling to reconcile this advice with the stated max capacity for SQL Server - a database size of 524,272 terabytes, with table rows limited only by "available storage".

Based upon those figures, the table described above could easily have centillions of rows (10 to the power of 303).

Ah ha you might say, there is a difference between CAPABILITY and PERFORMANCE.

But in virtually every question about SQL Server performance the answer is "It depends.... on table design and query design".

That is why I am asking this question. The table design couldn't be much simpler. Nor could the queries which are simple count(*) operations based on an indexed ID field.