WiFi repeatedly dropping

I've not changed a thing on my MacbookPro (Yosemite) in four months, but since just before Christmas, it's been constantly dropping my WiFi connection. The bars remain solid, but there's no connection. It's easy enough to get connected again by switching off WiFi and switching it back on again, and I'd go along with that solution except that the connection will drop again, often just a minute later. It will drop a dozen times or more in a day, more frequently in the evening.

Is this a known issue with Yosemite? Is there a fix? Is the connection any more stable under El Capitan? It's an annoyance I'd like to get rid of. Do any of you know how to fix this?

via ehMac.ca http://ift.tt/1Kdc2uE