Do you use the potential of your synthesizers?
You propably already own enough software synthesizers for the production of 10 albums.
Programming a software synthesizer can be tricky if you do not know all the terms and what every button does.
The architecture of your old synths can still be greate and you can boost it with new presets designed for the style of music you compose and produce.
If you are a skilled programmer you can use the full potential of your synths and if not you can buy sounds at a fraction of the price of a new synthesizer.