Hello! I would like to get a guinea pig. However I know it’s best best to get two. I was thinking of looking for one that wasn’t getting along with cage mates or just considering getting one that catches my eye and giving it loads of attention and possibly a mirror. But I would feel really guilty if I knew I didn’t give it the best life possible. Opinions?
Please always aim for two guinea pigs. They are group animals. You just can't give them the 24 hour stimulation that they need.
I currently have got a (dumped) guinea pig that has obviously been kept as beloved single from a young age at some point. So far, I have not been able to bond her with other piggies because she is scared stiff of even babies when she comes face to face with them. However, Beryn is still profiting massively from having piggy company all around her, and her favourite place is in the corner where four pens meet to sleep next to other piggies. she loves to roam and to say hello to all my other guinea pigs as long as they are safe behind bars!
If a guinea pig truly doesn't like others, then it can be kept as single as long as you are at home all day. But this should only happen after you have given a piggy every chance to date other piggies and to find one they click with.
The vast majority of single piggies are those that have been failed several times by humans - from being sold as singles or as a mismatched pair in too small a cage, then taken back as an 'unbondable' aggressor to live in isolation for the rest of his life and then being offloaded once they get older or boring...

Long time rescue experience has shown that over 95% of all piggies can actually be bonded and that even those that are not bondable are much more lively and happier when they can hurl abuse at other piggies next door!
I know of 6 year old single piggies that have finally found a new friend via rescue dating with a dedicated new owner - guinea pigs are never too old to find a new friend. My Calli, who has just celebrated her 9th birthday and was a depressed widow of 7 years when she came here can corroborate that - she has not made friends quickly, but is now very closely and happily bonded with a widow of mine and she has certainly not been depressed since her arrival here with so many piggies to interact with!
Even if you really want to get single piggies, it is much better to have two adjoining cages with interaction through the bars for ongoing stimulation and interaction. Guinea pigs really rely massively on this. Recent research has clearly shown their social interaction is much more complex than previously assumed and central to their wellbeing.
Sadly Switzerland is still the only country where it is illegal to sell and own single guinea pigs - but their pioneering animal welfare law is the result of direct democracy and pressure from the grass roots, not of political will from above!
Companionship
If you truly only want a single pet, then guinea pigs are unfortunately not the species for you.