Hi Mark,
A Philippine passport is usually valid for 5 years. (Most others have a 10 years validity)
As far as I know this is still the case.

For renewals, my personal opinion and advice would be to minimise all risks and wherever possible renew a passport around 9months before it expires.
Many countries require passports to be valid for at least 6 months beyond the return date of a trip.
Also, there are more and more airlines getting pretty strict now and plenty won't even let you check-in to board if this 6 month rule isn't met. (Or at the very least cause lots of frustrations and hassles before allowing)

Having said that I do know of quite a few folks who have travelled home to Philippines with an almost expired passport and renewed it in Manila. But it does need some checking ahead of time, and to me it seems to be a risk too far.

Regarding your specific concerns about a trip to Spain, she'll need to get a Schenghen Visa.
Generally, the current requirements for her will be in line with this:-

Foreign nationals residing in the UK must have been granted leave to remain for more than 6 months

The applicant's UK visa must exceed the return date of the proposed trip by more than 3 months

The applicant's passport must exceed the return date of the proposed trip by more than 3 months and must have a full blank visa page for the visa