This year has been a big one for anniversaries. The Queen of England, James Bond, the handover, 25 years since Robocop; it's all happening. Cynics might think anniversaries are mere opportunities for gift card firms and manufacturers of bunting to make us part with our cash. And they, alas, are probably right. But when it comes to watches, a big anniversary is a rich source of inspiration for watchmakers.

One of the biggest events in the watch world this year is the 40th anniversary of the Audemars Piguet Royal Oak. Designed by the legendary Gerald Genta, the original Royal Oak was conceived in one evening in a process that would normally take Genta several weeks. Inspired by a diving helmet, the Royal Oak, with its steel and avant-garde octagonal case, became a style icon that is as fresh today as it was in the 1970s. For 2012, Audemars Piguet has launched a series of new Royal Oak watches but the more direct tribute is the Royal Oak Extra-Thin (bottom left). Sized at 39mm and coming in the classic steel, the Extra-Thin is a slight watch in keeping with Genta's sporty original. The dial design is as it was in 1972, complete with the petite tapisserie pattern. Features are kept simply to hours and minutes with the nod to modern watchmaking coming with the calibre 2121 movement that is an impressive 3.05mm thick. The Audemars Piguet Royal Oak Extra-Thin is priced at HK$176,000.

Certain watch brands are indelibly associated with a certain pursuit or sport. Tag Heuer, for example, has a richly deserved association with motor racing, although the brand's history is much more varied than that and its anniversary provides an opportunity to look at that diversity. The Tag Heuer Carrera Calibre 1887 SpaceX Chronograph (bottom right) has been created for two reasons. First, to celebrate the 50th anniversary of the first Swiss watch in space, after American astronaut John Glen took the Heuer 2915A stopwatch up into the heavens. The second, more timely reason is to celebrate the SpaceX missions to the International Space Station. The watch comes in steel and is 43mm, providing ample room for the chronograph sub-dials and a surfeit of writing, including the legend, "First Swiss Watch In Space". The Tag Heuer Carrera Calibre 1887 SpaceX Chronograph is priced at HK$48,500 and is limited to 2,012 numbered editions.

Not all anniversary watches have to be years and decades in the making, and not all anniversaries have to mark some seismic event, as is the case with the IWC Schaffhausen Ingenieur Automatic Hong Kong Flagship. Ostensibly released to mark the one year anniversary of the watchmaker's 1881 Heritage boutique, this particular Ingenieur Automatic is sure to appeal to local collectors. The watch itself is classically simple and harks back to the Ingenieur watches of the 1950s. The case comes in rose gold, which plays well with the clean, black dial. The back of the watch is see-through and stamped with commemorations. Priced at HK$150,000, the Ingenieur Automatic is limited to 188 pieces and available only from 1881 Heritage.