Claiming Dependents

In Step 1c of my W4 I checked Married Filing Jointly. I have no children under 17 or living at home. Step 3 states, if total income is less than $200k ($400k jointly) to multiply the number of other dependents by $500. I/we make less than $200k/$400k. Since I checked Married Filing Jointly in Step 1, am I supposed to/required to claim $500 for my spouse in this block, or is it optional? What are the pros/cons if I list her ($500) or not versus not listing her ($500)?

 

Also, work may be taking me away from home for more than six months out of the year. I will be residing in a extended-stay hotel, apartment, rental property during that time. Should I make changes to myW4 when this occurs? Will there be other tax issues or concerns when I file for 2022?