Road-warrior (well, air-warrior) here.
Never ever check in camera equipment. A tripod, perhaps, but no camera bodies or lenses or flashes or anything of the sort. If it ain't getting banged up by the luggage sorting system, or getting misdelivered/misrouted, then it'll get pilfered by the thugs handling checked baggage -- be that those supposed to check the baggage for explosives, be that customs or be that simply baggage handlers.
Yes, theft happens by all 3 categories of people accessing checked-in luggage -- the French press is lately a-plenty with reports of such going on at Charles de Gaulle airport near Paris, for example, but I've seen the same happen in other parts of the world - and prominently so in north america....
There's a reason why travel insurance will not cover checked in valuables, y'know.
Don't check anything in that you can't be without. Don't check anything in that might look "interesting" on a baggage X-ray. Don't check anything in that won't be covered by your travel insurance.
Get yourself an IATA-sized carry-on (I use a Rimowa pilot case), and only fly airlines that respect IATA recommendations for carry-on. Also, avoid regional jets and turboprops, if at all possible (BAe's are particularly bad in terms of carry-on space). If you need more gear than what can be in a carry-on, then you need to contact FedEx
My Rimowa easily fits a full sized DSLR and 3-5 lenses, with plenty of room to spare.
In 15+ years of flying >150K BIS-miles/year, I've never had to gate-check a bag (and I'd refuse to do so if it contained valuables / a camera). On the other hand, I also carry a "reasonable carry on" with just valuables/necessities, as opposed to the "kitchen sink moving truck" that I see others lug along on most US domestic flights.