With 1:2 and 1:5 you can safely trade without leverage, the risk of ruining your account is low. But I wouldn't say the same for 1:100 leverage and for FX trading, you can easily enter period of long-term trend against you where your deposit won't sustain the move.
It is just a tool to limit loss and One can trade without it any time he should not depend on stop loss totally it is not a final way to manage your risk. Do trading with or without but keep in mind risk management is your main goal, it is up to a trader how he deals with the risk by monitoring trades or uses any tool for this purpose.
I once read that some analysts don't use stop-losses since we should sell a stock if your initial investment thesis proves incorrect, but if the stock drops for no good reason and your thesis holds, you should be buying at the lower valuation, rather than selling.