Electronic – Are the 2 terminals of an incandescent bulb lamp equivalent

Most light bulbs have a number of service hours designed in. This is achieved fairly accurately and on purpose during manufacturing. Consumer grade light bulbs burn out faster and the awful truth is that in that way the manufacturer ensures it can keep producing the light bulbs and make money. The main cause is the tungsten filament slowly evaporating until it gets too thin to carry the current. The trick during manufacturing is to etch the filament to a carefully designed thickness so the lifetime is reduced programmed.

The origins of programmed life light bulbs began with the Phoebus Cartel in 1924.

There are also light bulbs with a special stronger filament (basically they skip the 'etch-cycle'), these are for use in high reliable applications and last longer. They are commonly used in places that are hard to reach and are more expensive. Not sure about the proper name of these light bulbs. Because of the extended life time these bulbs are more expensive as a manufacturer has only limited room for producing spares. (What need is there for spares if the bulb doesn't fail?)

Where Australia and EU banned the consumer grade bulbs, the strengthened filament is not banned because of its specialized application. The latter type is just not available in your regular shop around the corner.

You could easily connect them all in parallel. or in any grid ie (3*10 or 6*5) and just control the input to the grid independently. As others have said incandescent bulbs is mostly a resistive load. If you go with ,say 5 in series and each of those 5 is in parallel then you would require 7.5V @ 1.8A. Choosing a configuration is simply a matter of what you have available.

Except for requiring more power than LEDs the incandescent bulbs can be pwm much easier. You might even be able to get away with a much lower switching frequency because the bulbs will tend to filter higher frequencies.

Series is easier to switch m but if one bulb do fails , the whole light fails. Going parallel you need to switch a higher current but its trivial to find a blown bulb. Using a grid like arrangement mixes these two features partially so you get lower switching current than when all is in parallel and its easier to find faults than when everything is in series.