Purchased/work device:
2007: Original iPhone (8GB)
2008: iPhone 3G (black, 16GB)
2010: iPhone 4 (black, 32GB)
2011: iPhone 4S (white, 32GB)
2012: iPhone 5 (black, 32GB)
2013: iPhone 5S (silver, 16GB, work device)
2014: iPhone 6 (space grey, 64GB)
2016: iPhone 7 Plus (white, 128GB)
2017: iPhone 8 Plus (space grey, 256GB)
2018: iPhone XS Max (silver, 256GB)
Skipped:
2009: iPhone 3GS (not enough difference in physical form factor)
2015: iPhone 6S (not enough difference in physical form factor; still in iPhone 6 contract)
2017: iPhone X (really wasn't sure on Face ID and hated the look of the notch, which has since grown on me)