I've had several expansions of a focus. one major change and several additions.
In the 90's started with getting all figures and vehicles/playsets that I could. Then I expanded it to included box vehicles/playsets in the early 2000's, followed by MOC.
I added to it further early 2002 to get the first 20 on Palitoy cards, followed by ESB Palitoy cards towards the end of that year.
By this point I began to consider selling of the Kenner run as I had them all on two cards and space was a premium.
2003 I added the POTF MOC figures, followed by Droids and ewoks as I wanted to focus on something else due to the difficulty of getting Palitoy MOC.
2004 I picked up all of the ESB characters on 30 backs, so changed a general Palitoy carded focus to a debut one, getting rid of most of the non debut Palitoy cards (some of those I regret parting with, but most I have managed to get again when focus changed again!)
2005 I started going for Palitoy character runs (hence trying to get back previous ones I'd sold)
The next few years that was where I stayed, though at some point...and I can't remember when, I went for Trilogo miscards.
By 2007 I decided to switch entirely to Palitoy only so all remaining Kenner (including a complete set of POTF Droids and Ewoks) went, and I just kept the 21 back Fett and VC Jawa. I even found the last pictures before/during the change...
http://www.starwarsforum.co.uk/viewtopic.php?f=2&t=16825
Palitoy and Miscards has remained my main focus since 2005. A long the way I have made several additions.
I decided to get the Palitoy 12" figures (Luke & Leia) and the 7 Palitoy Diecast vehicles. They seemed to fit in well with my focus. However, being a collector it was difficult to limit myself and it turned into aiming to get a complete 12" run and last year I completed all the diecast...kenner as well :shock:
I added the bop bags too and in recent years expanded to include all things Palitoy Star Wars...weapons, boards games Playdoh, kite etc.
Last year I finally gave in to the temptation and started on the Micro line. Wanted to for years but managed to resist.
Essentially, collections can change in one way or another all the time. It keeps it interesting and varied. It also helps when money/availability are limited in one section of your collection. That said, all the things I started collecting meant that last year was probably my busiest ever collecting year. If I get the chance I will take a picture of everything 2015 brought my way!! 8)
The real test for me now is what happens when I get a display room. It's been 5 years since my collection has been boxed up. Some parts of it I've not seen in that length of time and so many new bits have been added, some before I had to take it all down, so have never been on display.
Once I see it all out again I may decide that actually it doesn't appeal to me anymore and there could be the need for a major shake up. I also don't think I will ever find a way of displaying it all anyway so some may have to go! hopefully this year I will find out what the next stage in my collecting will be!