Holidays are over and riders are keen to get back to riding, plan their coming show season and fulfill new year resolutions. However, if your horse had a break from couple weeks to a month that means his fitness level is most likely OK but his mental readiness for work is not that sharp. In terms of mental fitness each horse reacts differently to a break. Some feel like even after a month they have never missed a bit, others, after one week need a few riders to get back into routine again. Usually, the horse reverts back to it's original or recurring training issues. For example, lazy horses with consistent work tend to be less lazy but revert back to being lazy when left out of work. Same happens to spooky horses, horses who argue about many things, sensitive and overreactive horses. This tendency creates a vicious cycle that makes riders who tend to ride inconsistently to feel stuck in their work because after each break they need to spend a few rides to restore their horse's mental readiness for work. If the break happens again they are back to the beginning!

If you know that your horse falls into one of the above categories you must recognize the responsibility of either working your horse very consistently or not have big plans and show ambitions. Expecting your horse to be ready to do his job without consistency in the training is not fair for the horse. Said that there is a way to be able to juggle busy life, work, family and training your horse. I am going to list options and ideas to help you find a way to continue training your horse without feeling a huge pressure of time restriction.

The minimum number of work sessions per week to create progress is 3. Twice a week keeps the horse fit at the level they are now and consistent enough to keep their mind in work as long as your horse is not super spirited and high strung one. I work my horses 4 times a week and in winter months there are some weeks where I do 3 times per week.
Not all of the working sessions must be riding - lunging, work in hand, driving, obstacle games require less time to get the horse ready and to spend working. Because fitness of the mind disappears faster then body fitness any work with your horse when you ask him to do something will keep him mentally fit.
Manage your time well. Sit down and create a time line how much you need for each task - driving to the barn, catching your horse, grooming/saddling, riding/working, cooling down, untacking/grooming, feeding and putting him out, driving to home/work. Do not deviate from that time line, stay focused and efficient, chat with others if you want as you are getting ready but do no stop to chat. Have a plan for your ride/work session so you do not get carried away. My time from the moment I park at the barn where Santo is now to the moment I drive away is 1 hour 40-50 min, this gives me 45-50 min of pure work time which is huge. If I short on time I do 30 min work in hand without saddling him which can cut my time to an 1 hour total.
If you absolutely know you cannot commit to 3 times per week half-lease your horse to a trusted rider. Asking someone to ride for free usually doesn't work. It is amazing how many girls whine they want to ride but do not have money. The moment opportunity presents itself they are busy, skipping rides and being irresponsible. Asking for money makes people actually come to ride because they paid for it.
If you have money to pay a trainer/instructor to work your horse once a week or on occasion you cannot make it it is money spend well as long as you trust the trainer and agree with the work done to your horse.
I am not big fan of an option of sending a horse away for training. Several reasons - your horse ends up fitter than you, you have no idea what is done to him, if he learns something new that you do not know you must take time to learn that to. Do not assume it will all go smoothly just because he learned it.
If you go south for winter 1 or 2 months (Canada's popular option) and you do not take your horse with you find someone very trustworthy to work him regularly. This will be the only time when sending your horse for training may be a good option if you want to be ready for the show season. However, choosing that person is like choosing a babysitter for your children... I never had one for my son. He spent a fair amount of time in horse barns... :)