BRM is always an interesting discussion. For me, your personal circumstances and the type of poker player you are play a major factor in the thought process. Here are my simplified thoughts on approximately how many buy-ins each type of player. Of course some players may fit into more than one category, or may be more risk taking / risk averse, but I think these (broad stroke) categories act as a pretty good guide:
The Casual Player:
They have some spare cash and are happy to throw it on a
poker site whenever they fancy a gamble. They can reload basically whenever they feel like it. BRM required: 1-5 buy-ins.
The Enthusiast:
They take the game fairly seriously, but poker is still very much a hobby. They try to make their deposits go as far as they can, but can reload from real life funds if needed. BRM required: 25-50 buy-ins.
The Aspiring Reg:
The guys that dream of making it. They still have a full time job and solid income with poker as a small side hustle. They want to build their bankroll and progress in stakes so that small side hustle turns into a genuine income stream. BRM required: 75-150 buy-ins
The Reg:
They are a solid winning player making fairly consistent money from poker. They still have a "normal" job, but maybe not full time so that they can focus more time on playing poker. They rely somewhat on their poker income, so they must limit their risk of ruin as much as they can. BRM required: 150-250 buy-ins
The Pro:
Their sole income comes from poker. The pay their mortgage and bills and feed their family from what they win at the tables. Going broke for them is not an option so their BRM much be the strictest of all. BRM required: absolute minimum 300 buy-ins.
The Loser:
It really doesn't matter how good you are at BRM, if you're a losing player you will never have enough buy-ins. BRM required:🏧