Do you get raises at work? Do you ask for them?

[Seafog]

I was pondering this, in the past I either got annual raises based on performance, or I was working at rates I set when being a nanny.

I am in a new job of five months, and got a raise this week that they didn't even tell me about, it wasn't until I reviewed my pay stub I saw the increase.
Is this usual?

Part of me wonders if by giving a small raise without asking, they can avoid a bigger raise (should I ask for it) at say the six month mark, or one year anniversary?

Just looking for feedback/to see if anyone else has a workplace like this...

Is it a raise or the increase of personal allowance?

For sure a raise, we don't get a personal allowance

Could it be to do with a change in tax code as we're in a new twx/Financial year that started 6th April? Personal allowance went up - that's the amount free from tax everyone gets

Edit to add: UK tax system has personal allowance

I was a manger in a multinational and the way it worked there was that each manager is responsible for managing her direct report's pay curves. The pain curve is a chart that shows how with each year of experience, assuming an average performance, wage should go up incrementally. For outstanding performers, there is another curve above the average, which gives the report more aggressive pay rises, below the average there is a curve for those who are underperforming where the pay curve is much slower. Typically the beginning of the curve (the first five years) is steeper, so you notice these rises more, and over the years it flattens out. Short answer, yes, you could get an annual pay rise. My advice is to always discuss performance with your manager at least once a year to understand if you are performing against expectations, above, etc. You should then expect an increase each year according to that performance.

At five months it may have been they review annually and so they included you anyway, which is rare actually
Just ask why!

Followed the advice, got ahold of my manager, we all got raises as the minimum wage went up, and she wanted us to all be ahead by the same amount (not on minimum wage, just staying ahead at the same rate)

Thank you all for the help!