Really common. I have several sources that I use for things like that. Mainly "hobby king" but I haven't used them in a while though, They used to have the main warehouse in Hong Kong but they branched out and had warehouses in the US, EU etc and it was fast and easy to get what you needed. I'm not sure its still that way and ordering from China isn't the best way to go if you just need one little thing. You need to scour the internet to find an RC type supplier that's UK based so you can get your stuff fast and easy. When I was building a lot I bought lots stuff extra to have on standby because it seems like you always are short some small part. I have tons of stuff available and can build almost any type of connector I need If I don't already have one.