A contrary voice.
I have had a few horror sets of rental equipment.
I originally bought my own kit after a vacation to the Canary Islands (~1990) where the gear was dreadful, I should have aborted when I saw the Kit but desperate to get wet I went forward.
More recently on short trips where I decided to rent rather than slep my gear I have had regulators that were very wet breathing, an serious problem in salt water for me, BC's with sticky inflator buttons, a real pain when you try for a puff of air and you get a 10 second blast that fully inflates the BC, and everything ill-fitting, uncomfortable, and unfamiliar.
Yes slepping gear around the world is a pain in the a$$, however it is yours and you should know it works (do a couple of pool sessions before going), it will be comfortable, etc.
personally don't worry about fins but take neoprene socks and blister pads, thats the one item that I will rent by preference rather than carry.
Dodgy gear is the one thing that can put you and/or your wife off diving forever.
Just my 2c worth
Victor