Good afternoon Spudly
Sheepdog is correct about the liquid damage issue, it is an industry term but doesnt mean that the handset has been immersed in liquid, merely that the unit has come into contact with moisture. Contrary to popular belief an iPhone indicator is not that easy to trip, whilst the indicator can be seen in the headphone jack and the connector port the reverse of the indicator is the sensitive side so the moisture can only turn the indicator pink from the inside of the unit NOT by touching the outward facing side. One of the key things to bear in mind about an iPhone is that it is handled significantly more than a standard phone, Apple have studied usage and have come up with a figure of 19xs more handling than most other units, this will take its toll.
Something important to note is that iPhones are not repaired, the £139 is for a replacement unit (heavily subsidised by Apple), no other OEM offers this, if any other unit is liquid damaged this is classified as BER (beyond economical repair) through customer damage and you would have to claim on your insurance or buy another handset.
In terms of putting your handset in a cup of cofee......... no liquids are allowed into the plant
and to be brutally honest there would be no benefit in doing so, financially or otherwise liquid damage is probably the most emotive subject I have to deal with!
Again being honest, you may need to look at how you use your handset, if this is the 2nd instance of liquid damage there may be something you are doing that inadvertantly exposes your phone to excessive moisture.
I hope this helps
KR