You should probably be guided by what the MSDS sheet for your product says. One common risk is becoming sensitized which could mean no more kayak construction or at least not kayaks that involve epoxy.

I don't think it is good practice to rely on how much something smells. Materials that don't smell may be worse than ones that do because you don't realize how much you have inhaled. A lot of bad things don't smell. Respirators are cheap.

Ric