somehow I'd find this more expressive (and precise) if it was like:
```php
$this->cacheResponseFor(7, self::DAYS); //instead of just 7
$this->cacheResponseFor(15, self::MINUTES);// instead of 1/96
$this->cacheResponseFor(12, self::HOURS);// instead of 1/2
```

the constants DAYS, MINUTES and HOURS would just be integer multipliers for the correct amount of seconds.