Building a savings buffer or paying off interest-free debt?

[FreckledLeopard]

So, I shall shortly be in a wholly new position and (hopefully) be able to start saving around £1000 per month from May onwards (school fees finishing, hurrah!).

Bit of background - I'm mid-thirties, had DD young, working full time, paying into pension scheme (but need to up my contributions). I live with DP (not DD's father). I'm the higher earner of the two of us.

DP has £4,000 on an interest-free credit card, payable (at the 0% rate) over 48 months. When May comes around and I'm in a position to start saving, I wanted initially to get a bit of a buffer behind me (maybe £3,000 or so) and then pay off DP's credit card (over four or five months).

DP, however, has said he thinks it might be better for us to establish a bigger buffer initially, leave the credit card being paid off at £100 per month over the four years, and instead of paying it off, over-pay on the mortgage.

Other than the mortgage and 0% credit card, we have no debt, but no savings either. Would people prioritise building a buffer, over-paying the mortgage and leaving the 0% card, or clearing the card? In theory, we'd save more money leaving the debt as it is, overpaying the mortgage and building a savings buffer, but I do worry about having credit card debt.

Any words of wisdom, please?

Thanks in advance.

I think he's right, as long as the CC will be paid off in the 0% period and you don't put additional spending on it, I would build a buffer and pay off more on mortgage

Thank you! I suppose logically it makes sense, but I suppose I always thought that clearing credit card debt would make more sense than mortgage debt, though when you do the sums, it makes sense to overpay.

That's just because CC debt is typically more expensive, obviously not the case at 0%

I wouldn't worry about the CC either. I'd probably put money in a pension. It comes out of gross salary so it's cost effective. You're also young enough for the new lifetime isa. I'd probably put a bit extra towards the mortgage too. In terms of rainy day savings, you definitely need those. 6 months living expenses are usually recommended but it depends on how secure your jobs are and whether you'd cope if one was out of work.