I'll go with "Have you got another pair of hands to help you when needed?".
This can be taken in a number of ways, for example help if you're ill or in an emergency. However, what I really mean is have you got anybody to help you shift heavy objects, hold things in place while you screw them to other things, that sort of thing.
For example, I spent an age welding two bits of metal together this afternoon because I was on my own and couldn't get them to line up properly without being held. Another pair of hands for 30 seconds would have saved me about 20 minutes.
We have a fantastic neighbour who's always willing to lend a hand, but I do often wonder how on earth we'd cope without him!
My other pearl of wisdom is "It's far easier to keep things ticking over than it is to break new ground". For example, the first batch of broiler chickens we had required buying heat pads, feeders etc, building a brooder, then making a house for them, fencing off a run, etc etc - probably one man-week's worth of effort. The second batch we had required none of that stuff, as it was already there.
With this in mind, we set a limit of no more than one new species per year. This has served us very well so far, and has just about
stopped us from biting off more than we can chew!