Anyone recommend magnifying glasses suitable when installing decoders?

They're not that small   

If you are soldering onto tiny decoder pads then you might well need magnification. There are many cheap magnifying spectacles on eBay. Go for a low to medium magnification to give a reasonable viewing distance. If you model in N you may use them a lot, so you may find it worth splashing out on an Optivisor.

Thanks Longbow, very useful.

ntpntpntp; laughter's the best medicine!

Once one acquires 'middle age', a collection of reading specs of various strengths is a great asset! 

I bought my first pairs in a UK poundshop but now buy them (usually from China) for less than a couple of quid each on ebay. Don't forget the plus or minus signs on the strength. I own a couple of pairs suitable only for seriously long-sighted folk which I ordered in error!