Advantages
Supervision, while one answers phone, goes to wc, washes up etc there is someone else to do an activity/supervise the children
Hygiene, someone can wash up/sweep etc after an activity/meal while someone is supervising so the washing up doesn't build up cos you had to go change a nappy or
Smoother Naptimes & arrivals, if a child needs more attention to help settle when arriving or to sleep then the care of the other children isn't compromised
Confidentiality, someone to discuss issues with without breaching confidentiality, how to approach a parent or deal with a behaviour issue or how to write a policy or even just how the day went etc
Possibly can split up at school collection times to collect from different schools or to have naptimes continue uninterupted indoors while one goes to collect
Disadvantages
Keeping to the required child ratios, if you want holidays at different times,
Planning for maternity leave, sick leave etc;
more chance of having to close - 2 people and their families who can become sick or need compassionate leave for funeral etc
If you are both childminders in your own right, only the person who owns the property can claim the utilities & wear & tear allowances.
If you're working with a hubby/partner can your relationship stand 24/7 togetherness
Do you split the income 50/50 or allocate children to each person?
If you work together as equals, how you will resolve issues where you don't see eye to eye?
If one is employed by the other, sorting out tax & NI, maternity pay/sick pay etc. Redundancy, sacking issues
Whistleblowing policy
Childcare income is irregular, when children leave and vacancies are not filled immediately will there be enough to pay you both?