“Best by date” true for bay leaves

Dried herbs really do only last around six months, certainly no longer than a year. They're generally easy to get in small quantities, though.

Spices are trickier. They'll generally last rather longer, but the time will vary. If the spice is used for the colour and/or heat (e.g. turmeric, chilli) it will generally last much, much longer than one used for its smell and/or taste. Whole spices last much, much longer than pre-ground; I generally buy whole spices from asian stores, they sell them in much larger amounts for the same prices as supermarkets; and use a coffee mill to grind the right amount just before cooking (and keep a separate one for coffee!).

If kept in the dark, in a dry, clean, airtight glass container, spices and dried herbs will certainly not become health hazards, and should not pick up unpleasant tastes or odours. The strong-tasting / strong-smelling ones will, however, lose taste and smell, eventually almost completely; since that is the whole point of using them, you might as well not bother once they're off.

There is no reason to worry. The worst thing which can happen is that a piece of bay leaf, being somewhat hard, can lodge somewhere in your digestive system, necessitating a trip to ER. But a medical paper on the topic starts its discussion section with the sentence "Reports discussing ingestion of bay leaves have been exceedingly scant". They only cite 10 references in the period 1950-1990, and most of these are general studies of foreign bodies in the esophagus, not specific studies of bay leaf ingestion.

Given how often bay leafs must find their ways into people's digestive systems (they feature in our food), it is safe to conclude that only a tiny fraction of ingested bay leafes cause problems, else there would be more studies mentioning such cases. The same is true for side effects different from mechanical obstruction: if this had happened, somebody would have published it.

The paper I mentioned is "Bay Leaf Impaction in the Esophagus and Hypopharynx" by Stephen K. Buto, MD; Tat-Kin Tsang, MD; Gerald W. Sielaff, MD; Laurie L. Gutstein, MD; and Mick S. Meiselman, MD. Sadly, it isn't freely available (I could read the full text because my uni has a subscription).

I guess that if you are working as a cook, your workplace may decide that even if the chance for a customer choking on a bay leaf is something like one in a million, they'd rather instill removing bay leaves from dishes as a policy. Probably prudent, although there are more important risks to care about.