All components shelf life depends on storage conditions and type of packaging. The main concerns with the storage of SMT passive components is humidity content, temperature, and tape & Reel degradation which could ultimately affect solderability.

Electronic devices are available in many package types and can contain semiconductors, magnets, capacitors, and resistors. Precautions against ESD (electrostatic discharge), moisture, and contaminants need to be considered for electronic devices.
 
The shelf life of resistors is determined by the integrity of their termination finish, which is dependent on their storage conditions. They will generally exhibit very little degradation for 2 years if stored under the following conditions:
Temperature: 40 to 90 degrees Fahrenheit
Humidity: 25% to 65% Relative Humidity
Parts are not exposed to direct sunlight or sulfur containing materials.
 
Microhm warrantees its products for one year from date of shipment. (Carbon Composition resistors are highly hygroscopic; therefore they must be stored in their sealed bags with desiccant until just before use. These resistors have a maximum shelf life of six months if stored in the sealed bags. )
 
Handling considerations involve ESD and environmental protections.
Shelf-life considerations involve solderability, MSL, and open-bag floor-life conditions. Storage considerations involve proper bagging and environment.
 
When using tape-and-reel packaged devices, the cover tape should be removed at a rate of 10 mm/s or less and at an angle of 165 to 180 degrees from the carrier-base plastic in order to minimize ESD generation.
 
SMD product, like SMD resistor, can be sensitive to picking up moisture within the molding compound of the package and, when undergoing board solder reflow, can have delamination occur between the molding compound and the lead frame. MSL classification (J-STD- 020D.1) gives a rating to each SMD package type, from MSL 1 to MSL 3, at a reflow temperature of 260°C or a lower temperature for some package.