Right now I have a Canon EOS 5d Mark IV camera. 

Some of my friends have 2 cameras which is useful when you need to use different lenses and the environment or the time does not allow you to change the lenses. However, carrying two cameras instead of one would be for me a bigger challenge.

Another dilemma is whether to use only Canon own lenses, or to buy also Sigma or Tamron lenses too. I did a compromise and use a mix of Canon, Tamron and Samyang lenses as per below:

Tamron SP 150-600 mm   F/5-6.3
Canon EF 100-400 mm  1:4.5-5.6 L IS
Canon EF 70-200 mm 1:4 L IS USM
Canon EF 100 mm 1:2.8 USM
Tamron SP 24-70 mm F/2.8 Di VC USD G2
Canon EF 50 mm 1:1.8 II
Canon EF 16-35 mm 1:2.8 L
Samyang 2.8/12 mm 1:2.8 ED AS

Then I have the usual “other” staff, like a good Manfrotto tripod, extention tubes, 1.4X focal multiplier, Canon  Speedlite 430 EX II flash, Canon ST-E2 speedlite transmitter and recently a procured a Pluto trigger