The palace come under pressure (in March) from politicians/media to celebrate her Sapphire Jubilee. But according to people at the Palace, the theory was that the public will get a bit sick of jubilees if you have too many of them. Far better to focus on the really big ones, and mark the minor anniversaries in a low-key way. So the next large-scale celebrations will be in 2022, when the Queen celebrates her Platinum Jubilee (it's in fact already being planned).
Wedding Anniversaries:
The Queen's wedding anniversaries have not been celebrated with super-large-scale celebrations such as her Silver, Golden and Diamond Jubilees or the large celebrations of her 60th, 80th and 90th Birthdays, but they have been marked.
The Silver Wedding Anniversary 1972:
November 20th: There was a carriage procession from Buckingham Palace to Westminster Abbey where they attended a Service of Thanksgiving. (televised)
There was also a privat party at the palace in the evening.
The Golden Wedding Anniversary 1997:
November 19th: They attended a lunch at the Guildhall, where HM said ''he is someone who doesn't take easily to compliments, but he has, quite simply, been my strength and stay all these years and I and his whole family, in this and many other countries, owe him a debt far greater than he would ever claim or we shall ever know'. (televised)
They attended a golden Gala at the Festival Hall in London in the evening. (televised)
November 20th: They attended a Service of Thanksgiving at Westminster Abbey. (televised)
There was a private party at Windsor Castle in the evening.
The Diamond Wedding Anniversary 2007:
November 18th: Charles hosted a dinner for his parents at Clarence House.
November 19th: A National Service of Thanksgiving was held at Westminster Abbey. (televised)
The Platinum Wedding Anniversary 2017:
It was (after the Sapphire Jubilee discussions in March) the opinion of several royal watchers – that the Palace instead wanted to celebrate the Queen and Philip's 70th wedding anniversary in November, but we haven't heard anything since.
If it's going to be marked (as I think it will), then I think we'll see a private dinner (maybe hosted by Charles) and a televisied Service of Thanksgiving at Westminster Abbey.