Every business was a start-up once. The Small Business Association states that 30% of new businesses fail during the first two years of being open, 50% during the first five years and 66% during the first 10. 

Google was a start-up, as was boo.com. If you had share options at Google you are now a zillionaire. If you had options in boo.com that raised $135m and went bust in a year - they are worthless. AltaVista was one of the largest search engines and valued at $2.3b within 4 years of launching, acquired for, not a lot, by Yahoo and shut down. For all the well known digital start-ups that failed, such as Friends Reunited and Stumble Upon. there were, and are, thousands that never made the headlines but at some stage have ceased trading or will fail. It's business.

Many candidates are attracted to start-ups for all the right reasons. Something new, somewhere where you can make a tangible difference and if have backed the right horse, could make you wealthy. You have a one in three chance of getting it right - not the worst odds.

Lime is a competitor in the mobility space providing bikes and scooters to rent. It must be an exciting place to work but what is clear is that start-ups are backed by investors. They don't care so much about your flexible working, whether or not your dog can come to work or you have unlimited holiday and a massage every Friday. They want a return on their investment.

When things don't go to plan, it's the people who get the chop. So after having those share options and you dreamed it would make you a millionaire as you burnt the midnight oil to make a difference, remember that nothing is certain other than investors who rightly expect a return and to get that, your job may be on the line and your shares worthless.

Google was a start-up once and there will be other unicorns around and yet to come.