A lot of confusion around row counting doesn't actually come from miscounting the fabric at all — it comes from not being sure which number a pattern is actually asking you to track. Patterns frequently mix two different counting systems within the same set of instructions: an absolute row count (row 1 through row 40, sequentially, from the start of the piece) and a repeat count (rows 1 through 8, worked as a block, repeated six times). These are genuinely different things, and treating them interchangeably is a common source of errors.
The distinction matters because the two numbers answer different questions. 'What row am I on overall' tells you your total progress through the piece. 'Which repeat am I on, and which row within that repeat' tells you what stitch instruction to actually follow next. A pattern with an 8-row repeat doesn't repeat the instruction 'row 23' — it repeats 'row 7 of the repeat,' which happens to fall on absolute row 23 the third time through.
How to tell which one a pattern is asking for
Read the pattern's instructions carefully before starting, specifically to identify its structure. If you see language like 'repeat rows 1-8 a total of 6 times' or 'work in pattern as established,' the pattern is built around a repeat unit, and your job is to track two things: which row within the current repeat you're on (1 through 8), and how many full repeats you've completed so far. If instead you see something like 'on row 24, decrease as follows,' the pattern is referring to an absolute row number counted from the very start of the piece.
Many patterns actually use both systems in different sections — a repeating stitch pattern for the body, with absolute row numbers called out specifically for shaping instructions layered on top. This is exactly the situation where it's easiest to get confused, because you're tracking your position within the repeat for the stitch pattern itself, while simultaneously tracking absolute row count to know when a shaping row is due.
A method that keeps both numbers straight
The cleanest approach is to track both numbers explicitly rather than trying to derive one from the other in your head mid-row. Keep an absolute row count going for the entire piece — this is your permanent, ongoing record. Separately, keep a repeat counter that resets back to 1 every time you complete a full repeat cycle — this tells you which line of the stitch pattern instructions to follow right now.
If your pattern has an 8-row repeat and you're on absolute row 35, a quick calculation (35 divided by 8, remainder 3) tells you you're on row 3 of your fifth repeat. Doing this arithmetic in your head every single row is tedious and error-prone, which is exactly why it's worth tracking the repeat position directly and separately rather than recalculating it from the absolute row count each time.
Where this specifically causes shaping mistakes
The most consequential version of this confusion happens when a pattern says something like 'work in established rib, decreasing 1 stitch every 6th row.' Here you need your absolute row count to know when the 6th row lands, while simultaneously needing your repeat position to know what the rib pattern requires on that same row — and the decrease itself might need to happen at a specific point within the rib repeat to avoid visibly disrupting the ribbing.
Tracking both numbers as genuinely separate counts, rather than trying to hold one derived from the other, is really the only reliable way through this. A counter or notebook that lets you log an absolute row total alongside a separate repeat-position note removes the mental math entirely, and mental math done under time pressure, mid-row, with needles in hand, is exactly where this kind of counting mistake tends to happen.