Hi Sarah - we were in exactly the same position as you last November. We'd wanted a dog for years, but with three cats (two who hated dogs with a vengeance), it wouldn't have been fair.
So when the old lady cat had to be put down (we'd already lost Charlie, her brother last Easter, sad they both lasted until 16 then went within 7 months of each other), we decided time was right.
We're now the proud owners of Roxy, our gorgeous black labrador *****.
Both my daughter and myself suffer from Asthma and it was the vet who recommended a lab for all round best for a family, including asthmatics! Neither of us have any problem whatsoever. Yes, they do shed fur, but any animal will when the central heating is on like at present - just get a good brush and this helps. We were used to hair shedding with the cats, so probably not so much of an issue for us.
I work in the mornings Monday to Friday, so Roxy is left on her own during this time. She doesn't seem to have suffered for it - she gets a good walk in the morning before I go to work, we have lunch when I get home and then spend a good hour or more out in the forest or park or wherever having a run, play in the afternoon. We also are lucky to have a large garden, so she can get out there as soon as I'm home. My DH also works from home usually one day a week, so she has company three out of seven.
I know there is a train of thought that you shouldn't leave a dog on its own AT ALL during the day. Sorry, but that's not at all realistic. We wanted to get a rescue dog - my previous dogs had been rescue dogs - but around here in the New Forest, their criteria is so strict it's a wonder anyone ever gets to have one. We were not allowed to . . . work, have small children, old people, go away on holiday; we had to have a minimum of 5 foot high fences all around our property (we live in the new forest, surrounded by field and farmland, have a 4 foot high bank where this is and 3ft fences with bushes in front either side of the garden where we have back on to neighbours gardens. This was not good enough for the resuce centres, we had to have 5 ft high fences erected. No thanks. We have wildlife which comes into our garden every day - badgers, foxes, deer. They can jump over the bank from the field and get back out again, but we have put up sufficient low rise fencing that Roxy can't get out. Let's face it, if a dog wants out, it will get out!
So that left us with a dilemna when we realised a rescue dog wasn't an option. I know so many people now, good, honest dog loving people, who have been turned away by rescue centres, made me feel much better, I can tell you!
So we looked at specific breeds and, after much research, decided that a Lab was the dog for us.
She's never (and is nearly six months old now) chewed any furniture - even being left alone. However, she does chew things - newspapers, boxes of tissues. She's a dog and if it's there for her she's play with it! We've learnt this. Labradors are also gluttons - they eat everything and anything!! Over the three months we've had Roxy, she's managed to snag and eat a pound and a half of grapes, a box of six eggs (OMG the smell that day!), half a birthday cake, a few socks, pair of nickers . . . but we've learnt how far she can reach on the side and everything is now (I hope since i'm typing this at work

) out of her way that we don't want her to have.
She's brought so much love, fun and joy to our household it's difficult to remember when she wasn't around.
She was actually bred as a gun dog, but they realised at a very early age that she just didn't have it in her, and she can be scared of her own shadow sometimes, but she's great, loves everyone and everything, all other creatures (our cat even tolerates her now, so long as she doesn't squish him when the cat decides to have a nap in Roxy's basket.
Our friends had a lab pup, we spent a couple of days with her before we decided to get one and that really helped.
Waffled on long enough now, but just to let you know I'm here if you need to ask anything on Labradors!
Have fun deciding and choosing, it's a life-changing decision.
Annie
