Credit card portfolio

Reward/cashback cards

• BA American Express which I will be cancelling soon
• SPG Amex which has my highest limit
• American Express Rewards card (clear one)
• NatWest Reward card for 1% cashback on the weekly Sainsbury's shopping and also 0.5% cashback on the mortgage payment each month (NatWest don't classify it is a cash transaction). I have also had the Reward bank account for ages, so I pay no annual fee for this card.
• John Lewis Partnership card when Amex is not accepted

0% interest balance transfer cards

• Barclaycard which has a 0% interest balance on it
• Lloyds which has a 0% interest balance on it
• NatWest 0% interest & no fee balance transfer card

Other

• Clydesdale credit card for emergencies
• B credit card for overseas purchases
• First Direct credit card just to avoid the £10 monthly fee for the bank account

In the long-term, I am trying to achieve the following:

1. Only the American Express Rewards credit card due to no annual fee
2. NatWest Reward card for the mortgage and shopping
3. John Lewis card for where Amex is not accepted and the NatWest card will be up to its limit with the mortgage and shopping balances
4. Barclaycard due to it being my oldest card
5. B card for overseas purchases

3 cards

1 with 0% interest and no foreign fees
1 with cashback
1 perfectly managed since the 90s for credit worthyness but otherwise sucks

I don't doubt this as I know it is perfectly feasible to have that sort of total available credit, but am wondering how you are managing to keep such a large amount at 0%, presumably using existing customer offers, without paying fees and if you are paying fees how you are managing to make sufficient profit to make it worth your while.

It is using only new customer offers, wherever a provider offers a no fee, 0% interest balance transfer offer. Occasionally an existing provider will be able to give a no fee, 0% interest offer, but that is very much the exception.

I transfer as much as possible to any new no-fee 0% balance transfer card, from the card which allows no fee money transfers (and which has a nil balance almost all the time). Then simply make a money transfer to my bank account. In theory, I could pay a few days of interest depending on the timing of the transfers, which would be peanuts, but in practice I've never paid any interest on a transfer.

Repeat this every 3-6 months (anything more will just lead to rejections), keeping an eye on used credit to available credit ratio and also total credit balance to gross income ratio. Whilst both are above 50% I find there is a lower chance of being accepted for new cards, so wait until an existing card's offer expires, is paid and off and closed, and then apply for new credit lines.

Funding of monthly repayments and final payment at end of offer period is planned around expected income and expenditure to ensure I can repay everything even if no new offers are secured. If necessary, some of the capital from the borrowing is kept in an instant access account (at 1.5% interest) to enable this. For example, in September I will need to repay £26,459 as multiple offers end at the same time, so currently a lot of funds are held in instant access accounts. Hopefully more borrowing is secured, freeing up capital for ISA deposits.

I'd love to have a back-up for the legacy no-fee money transfer card, as one-day that will be ended by the provider and it is pivotal to the games described above, but I haven't seen anything in recent times.