Many people struggle with correctly using the word practise/practice.

I have had the odd struggle myself, as when I was running a bookkeeping practice, I would also in the evenings practise the piano.

Let’s look at those spellings again, but broken down into two different sentences:

“I run a bookkeeping practice.”
“I am going to practise the piano.”

Before we go explore further, there is a caveat. The above distinction between spellings is in how the words are spelt/ in the UK, as well as in other international variants such as Canadian and Australian English.

The spelling practice is used when the word is a noun, i.e. an object. A bookkeeping practice, a dental practice, a legal practice, a medical practice etc.

The spelling practise is used when the word is a verb, i.e. an action. Piano practise, handwriting practise, French practise etc. The same theory applies to adjectives, such as practising the piano and practising handwriting.

This can get quite confusing in some sentences, for example, a doctor who practises (verb/action) medicine in their medical practice (noun/object).

Practise/practice can be difficult in some sentences. I can say that I am practising the piano, and that my piano playing will get better with practice. The former usage is a verb, whereas the latter is what is known as an uncountable noun.

When I was working as a copywriter, I would often write for a UK-based client on the same day that I was writing for a US-based client, and I would need to remember that the rules are different.

In the UK and variants: Practise (verb) and practice (noun).
In the US: Practice (verb and noun), practise is avoided completely.

Personally, I prefer the US approach. There is no real need to for the different spellings, if a sentence is well-written, in order to distinguish between them. The two spellings are likely to cause confusion and be misused. Reasonable people may disagree.

To summarise, the noun is always spelt as practice, whereas when used as a verb, it will be either practice or practise, dependent on local usage.