I have a number of guitars, some expensive ones, some not so.

I have to admit that any I don't wish others to play, if I go to a singaround, I tend to tune other than standard. If I take a cheaper one, I am more than happy to tune it normally and let others borrow it if they are careful.

I am still in the novelty phase with my latest toy, a carbon fibre Rainsong. I am not sure I want others playing it. Yet when I think about it, it is possibly the most mechanically robust guitar I own...

Songbob makes a good point about different sounds. The Rainsong has a very bright sound but if I wanted a more mellow sound, then the Fylde every time. It is not very often these days I get to perform a set on stage, (other than with the band) but if I do, then I have three guitars on there with me. The Rainsong tuned normally, the Fylde in DADGAD and my trusty old Jim Harley dreadnaught as a backup for strings breaking or refusal to stay in tune with either of the other buggers.

With the band, the Rainsong is now providing the acoustic sound and my trusty Strat' for the electric.

So I reckon if you can justify two guitars from a budgeting angle, then do so. Make sure the sound is very different to the other one, or use one for exploring different tunings. Either way, your overall experience will be enhanced.