Do credit catalogues normally give huge credit limits?

[ConcernedHedgehog]

wanted to boost my credit rating so a year back I took out a catalogue. I was initially given a £350 limit but I've never even owed that much what I normally do is order something worth approx £50 then pay it off in full within two weeks.
I've now got a credit building card which I use in a similar manner (£100 limit) and don't use the catalogue. My credit rating has improved hugely though.
However, they've bumped my limit up 6 times now. This time to a whopping £4000.
I find this quite scary and won't use it, given my income is just shy of £10,000. Is this usual? I find it really strange that they're willing to give me so much credit, £1000 maybe (though I wouldn't use it) but it seems madness that they'd let me take out basically almost half of my annual income, I wouldn't even afford the repayments...

I think it must be as the same has happened to me. They keep increasing my limit even though I've only used it once to purchase something. I think it's a bit naughty really. Today I got money off vouchers in the post and a letter reminding me how much I have to spend! Talk about enticing people to get into debt.

It’s not unusual. I don’t know why they go so high, presumably there’s some algorithm that recognises you’re not a ‘risky’ customer because it happens automatically.

I wouldn't even afford the repayments...

Which means you'd be paying the basic amounts each month and probably only just covering the interest and not denting the amount owed.

It's how they make their money I think. They don't want anyone overly risky who'll just never pay, but equally they don't want folks who just pay off their entire bill every month.

wouldn't even afford the repayments...
They only make money if you pay a lot of interest.