Unmodified oligos are stable. For long-term storage (up to one year), freeze DNA at -20° C. For even longer storage, freeze DNA at -80° C. 2. If the oligos are stored in solution, avoid repeated freeze-thaw cycles as this process can lead to physical degradation of the oligo. 3. If numerous experiments are planned, aliquot the sample and store at -20°C. 4. Careful handling is recommended to avoid possible contamination with nucleases or bacteria. 5. Twist DNA resuspension guidelines can be found here.