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6 guides

Guides for the things you do once and have to get right

Registering, closing a quarter, setting up an association. Whole tasks told from beginning to end, with the rule cited and no invented figures. When a figure changes every year, we say so instead of giving it to you wrong.

With the sources at the footReviewed in September 2026No figures that go out of date
Where to start

The one for you, depending on where you are

The six guides can be read in any order, but hardly anyone needs them all at once. This is the route people usually come by.

If you are…Start withAnd carry on with
Thinking of registeringRegistering as an autónomoThe one on expenses, before the first big purchase
Newly registeredHow to make an invoiceThe one on deductible expenses
With the first quarter upon youClosing the quarterThe tax calendar, so that you never have to look the date up again
Losing money on expenses you do not recordDeductible expensesThe one on the quarter, where they get applied
Setting up a non-profit organisationSetting up an associationThe one on collecting fees, which is what comes next
Chasing fees or monthly paymentsCollecting by direct debitIt works just as well for a club or a training academy

And if what you are after is understanding one word you have seen on a form or an invoice, do not start here: it is in the glossary.

How these guides are written

With three rules, and you notice them as you read.

Every figure carries its rule. When we say that the limit for a simplified invoice rises to €3,000 in hospitality, there is an article behind it and it is linked at the foot. Not because it looks serious, but so that you can check it yourself.

What changes every year is not given. The autónomo contribution bands move every year. A guide that publishes them will be wrong in twelve months' time and nobody will notice. We would rather say that they change and link to the body that sets them.

And we say what the program does not do. Cairos does not file forms with the Spanish Tax Agency and does not process registrations: it leaves the numbers ready. Putting it any other way would make for a more commercial guide and a disappointed customer on day one.

If you were looking for a word

These guides describe processes. For individual concepts — taxable base, prorrata, chargeable event, bill of materials, cooperative refund — there is the glossary, with forty-eight terms explained with an example and the mistake most often made with each one.

And what these guides describe, solved

Cairos keeps the invoices, the expenses and the forms with the same data, so the theory turns into boxes already filled in.

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